A couple of measures to speed up tab completion further.

src/com/massivecraft/massivecore/PredictateStartsWithIgnoreCase.java

@@ -1,13 +1,14 @@
 package com.massivecraft.massivecore;
 
+// Inspired by: String#regionMatches(ignoreCase, toffset, other, ooffset, len)
 public class PredictateStartsWithIgnoreCase implements Predictate<String>
 {
 	// -------------------------------------------- //
 	// FIELDS
 	// -------------------------------------------- //
 	
-	private final String prefix;
+	private final String prefixLower;
-	public String getPrefix() { return this.prefix; };
+	private final String prefixUpper;
 	
 	// -------------------------------------------- //
 	// CONSTRUCT
@@ -16,7 +17,9 @@ public class PredictateStartsWithIgnoreCase implements Predictate<String>
 	public static PredictateStartsWithIgnoreCase get(String prefix) { return new PredictateStartsWithIgnoreCase(prefix); }
 	public PredictateStartsWithIgnoreCase(String prefix)
 	{
-		this.prefix = prefix.toLowerCase();
+		if (prefix == null) throw new NullPointerException("prefix");
+		this.prefixLower = prefix.toLowerCase();
+		this.prefixUpper = prefix.toUpperCase();
 	}
 
 	// -------------------------------------------- //
@@ -27,7 +30,15 @@ public class PredictateStartsWithIgnoreCase implements Predictate<String>
 	public boolean apply(String str)
 	{
 		if (str == null) return false;
-		return str.toLowerCase().startsWith(this.getPrefix());
+		int index = this.prefixLower.length();
+		if (str.length() < index) return false;
+		while (index-- > 0)
+		{
+			char c = str.charAt(index);
+			if (c == prefixLower.charAt(index)) continue;
+			if (c != prefixUpper.charAt(index)) return false;
+		}
+		return true;
 	}
 	
 }

src/com/massivecraft/massivecore/cmd/arg/ARPlayer.java

@@ -1,13 +1,9 @@
 package com.massivecraft.massivecore.cmd.arg;
 
-import java.util.Collection;
-import java.util.Iterator;
-import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 
 import com.massivecraft.massivecore.store.SenderIdSourceMixinAllSenderIds;
 import com.massivecraft.massivecore.util.IdUtil;
-import com.massivecraft.massivecore.util.MUtil;
 
 public class ARPlayer extends ARSenderIdAbstract<Player>
 {
@@ -19,7 +15,7 @@ public class ARPlayer extends ARSenderIdAbstract<Player>
 	public static ARPlayer get() { return i; }
 	private ARPlayer()
 	{
-		super(SenderIdSourceMixinAllSenderIds.get());
+		super(SenderIdSourceMixinAllSenderIds.get(), true, true);
 	}
 	
 	// -------------------------------------------- //
@@ -33,25 +29,4 @@ public class ARPlayer extends ARSenderIdAbstract<Player>
 		return IdUtil.getPlayer(senderId);
 	}
 
-	@Override
-	public Collection<String> getTabList(CommandSender sender, String arg)
-	{
-		// Super Ret
-		Collection<String> ret = super.getTabList(sender, arg);
-		
-		// Filter Ret
-		Iterator<String> iter = ret.iterator();
-		while (iter.hasNext())
-		{
-			String name = iter.next();
-			if ( ! MUtil.isValidPlayerName(name))
-			{
-				iter.remove();
-			}
-		}
-		
-		// Return Ret
-		return ret;
-	}
-
 }

src/com/massivecraft/massivecore/cmd/arg/ARSender.java

@@ -15,7 +15,7 @@ public class ARSender extends ARSenderIdAbstract<CommandSender>
 	public static ARSender get() { return i; }
 	private ARSender()
 	{
-		super(SenderIdSourceMixinAllSenderIds.get());
+		super(SenderIdSourceMixinAllSenderIds.get(), true, false);
 	}
 	
 	// -------------------------------------------- //

src/com/massivecraft/massivecore/cmd/arg/ARSenderEntity.java

@@ -18,9 +18,15 @@ public class ARSenderEntity<T extends SenderEntity<T>> extends ARSenderIdAbstrac
 	// CONSTRUCT
 	// -------------------------------------------- //
 	
-	private ARSenderEntity(SenderColl<T> coll, boolean online)
+	private ARSenderEntity(SenderColl<T> coll, boolean onlineOnly, boolean playerOnly)
 	{
-		super(coll, online);
+		super(coll, onlineOnly, playerOnly);
+		this.coll = coll;
+	}
+	
+	private ARSenderEntity(SenderColl<T> coll, boolean onlineOnly)
+	{
+		super(coll, onlineOnly);
 		this.coll = coll;
 	}
 	
@@ -34,7 +40,8 @@ public class ARSenderEntity<T extends SenderEntity<T>> extends ARSenderIdAbstrac
 	// GET
 	// -------------------------------------------- //
 	
-	public static <T extends SenderEntity<T>> ARSenderEntity<T> get(SenderColl<T> coll, boolean online) { return new ARSenderEntity<T>(coll, online); }
+	public static <T extends SenderEntity<T>> ARSenderEntity<T> get(SenderColl<T> coll, boolean onlineOnly, boolean playerOnly) { return new ARSenderEntity<T>(coll, onlineOnly, playerOnly); }
+	public static <T extends SenderEntity<T>> ARSenderEntity<T> get(SenderColl<T> coll, boolean onlineOnly) { return new ARSenderEntity<T>(coll, onlineOnly); }
 	public static <T extends SenderEntity<T>> ARSenderEntity<T> get(SenderColl<T> coll) { return new ARSenderEntity<T>(coll); }
 	
 	// -------------------------------------------- //

src/com/massivecraft/massivecore/cmd/arg/ARSenderId.java

@@ -9,9 +9,14 @@ public class ARSenderId extends ARSenderIdAbstract<String>
 	// CONSTRUCT
 	// -------------------------------------------- //
 	
-	private ARSenderId(SenderIdSource source, boolean online)
+	private ARSenderId(SenderIdSource source, boolean onlineOnly, boolean playerOnly)
 	{
-		super(source, online);
+		super(source, onlineOnly, playerOnly);
+	}
+	
+	private ARSenderId(SenderIdSource source, boolean onlineOnly)
+	{
+		super(source, onlineOnly);
 	}
 	
 	private ARSenderId(SenderIdSource source)
@@ -30,7 +35,8 @@ public class ARSenderId extends ARSenderIdAbstract<String>
 	// GET
 	// -------------------------------------------- //
 	
-	public static ARSenderId get(SenderIdSource source, boolean online) { return new ARSenderId(source, online); }
+	public static ARSenderId get(SenderIdSource source, boolean onlineOnly, boolean playerOnly) { return new ARSenderId(source, onlineOnly, playerOnly); }
+	public static ARSenderId get(SenderIdSource source, boolean onlineOnly) { return new ARSenderId(source, onlineOnly); }
 	public static ARSenderId get(SenderIdSource source) { return new ARSenderId(source); }
 	
 	// -------------------------------------------- //

src/com/massivecraft/massivecore/cmd/arg/ARSenderIdAbstract.java

@@ -1,12 +1,13 @@
 package com.massivecraft.massivecore.cmd.arg;
 
 import java.util.Collection;
+import java.util.List;
 import java.util.Set;
-import java.util.TreeSet;
 
 import org.bukkit.command.CommandSender;
 
 import com.massivecraft.massivecore.MassiveException;
+import com.massivecraft.massivecore.collections.MassiveList;
 import com.massivecraft.massivecore.mixin.Mixin;
 import com.massivecraft.massivecore.store.SenderIdSource;
 import com.massivecraft.massivecore.util.IdUtil;
@@ -19,16 +20,23 @@ public abstract class ARSenderIdAbstract<T> extends ARAbstract<T>
 	// -------------------------------------------- //
 	
 	protected final SenderIdSource source;
-	protected final boolean online;
+	protected final boolean onlineOnly;
+	protected final boolean playerOnly;
 	
 	// -------------------------------------------- //
 	// CONSTRUCT
 	// -------------------------------------------- //
 	
-	public ARSenderIdAbstract(SenderIdSource source, boolean online)
+	public ARSenderIdAbstract(SenderIdSource source, boolean onlineOnly, boolean playerOnly)
 	{
 		this.source = source;
-		this.online = online;
+		this.onlineOnly = onlineOnly;
+		this.playerOnly = playerOnly;
+	}
+	
+	public ARSenderIdAbstract(SenderIdSource source, boolean online)
+	{
+		this(source, online, false);
 	}
 	
 	public ARSenderIdAbstract(SenderIdSource source)
@@ -49,7 +57,7 @@ public abstract class ARSenderIdAbstract<T> extends ARAbstract<T>
 	@Override
 	public String getTypeName()
 	{
-		if (online) return "online player";
+		if (onlineOnly) return "online player";
 		else return "player";
 	}
 	
@@ -94,28 +102,25 @@ public abstract class ARSenderIdAbstract<T> extends ARAbstract<T>
 	@Override
 	public Collection<String> getTabList(CommandSender sender, String arg)
 	{
-		// Create Ret
-		Set<String> ret = new TreeSet<String>(String.CASE_INSENSITIVE_ORDER);
-		
-		// Fill Ret
 		Set<String> names;
-		if (online)
+		if (onlineOnly)
 		{
-			names = IdUtil.getOnlineNames();
+			names = playerOnly ? IdUtil.getOnlinePlayerNames() : IdUtil.getOnlineNames();
+			
+			List<String> ret = new MassiveList<String>();
 			for (String name : names)
 			{
 				if ( ! Mixin.canSee(sender, name)) continue;
 				ret.add(name);
 			}
+			return ret;
 		}
 		else
 		{
-			names = IdUtil.getAllNames();
+			names = playerOnly ? IdUtil.getAllPlayerNames() : IdUtil.getAllNames();
-			ret.addAll(names);
+			
+			return names;
 		}
-		
-		// Return Ret
-		return ret;
 	}
 	
 	// -------------------------------------------- //
@@ -137,7 +142,7 @@ public abstract class ARSenderIdAbstract<T> extends ARAbstract<T>
 			if ( ! coll.contains(senderId)) continue;
 			
 			// ... and the online check passes ...
-			if (this.online && !Mixin.isOnline(senderId)) continue;
+			if (this.onlineOnly && !Mixin.isOnline(senderId)) continue;
 			
 			// ... and the result is non null ...
 			T result = this.getResultForSenderId(senderId);

src/com/massivecraft/massivecore/util/IdUtil.java

@@ -119,6 +119,9 @@ public class IdUtil implements Listener, Runnable
 	private static Set<String> onlineNames = new ConcurrentSkipListSet<String>(String.CASE_INSENSITIVE_ORDER);
 	public static Set<String> getOnlineNames() { return Collections.unmodifiableSet(onlineNames); }
 	
+	private static Set<String> onlinePlayerNames = new ConcurrentSkipListSet<String>(String.CASE_INSENSITIVE_ORDER);
+	public static Set<String> getOnlinePlayerNames() { return Collections.unmodifiableSet(onlinePlayerNames); }
+	
 	
 	private static Set<String> allIds = new ConcurrentSkipListSet<String>(String.CASE_INSENSITIVE_ORDER);
 	public static Set<String> getAllIds() { return Collections.unmodifiableSet(allIds); }
@@ -126,6 +129,9 @@ public class IdUtil implements Listener, Runnable
 	private static Set<String> allNames = new ConcurrentSkipListSet<String>(String.CASE_INSENSITIVE_ORDER);
 	public static Set<String> getAllNames() { return Collections.unmodifiableSet(allNames); }
 	
+	private static Set<String> allPlayerNames = new ConcurrentSkipListSet<String>(String.CASE_INSENSITIVE_ORDER);
+	public static Set<String> getAllPlayerNames() { return Collections.unmodifiableSet(allPlayerNames); }
+	
 	// -------------------------------------------- //
 	// REGISTRY
 	// -------------------------------------------- //
@@ -215,7 +221,9 @@ public class IdUtil implements Listener, Runnable
 		if (name == null) throw new NullPointerException("name");
 		
 		onlineNames.remove(name);
+		onlinePlayerNames.remove(name);
 		allNames.remove(name);
+		allPlayerNames.remove(name);
 		
 		IdData data = nameToData.remove(name);
 		if (data == null) return null;
@@ -243,10 +251,14 @@ public class IdUtil implements Listener, Runnable
 		
 		if (id != null && name != null)
 		{
+			boolean player = MUtil.isValidPlayerName(name);
+			
 			if (online) onlineIds.add(id);
 			allIds.add(id);
 			
+			if (online && player) onlinePlayerNames.add(name);
 			if (online) onlineNames.add(name);
+			if (player) allPlayerNames.add(name);
 			allNames.add(name);
 		}
 	}
@@ -336,9 +348,11 @@ public class IdUtil implements Listener, Runnable
 		
 		onlineIds.clear();
 		onlineNames.clear();
+		onlinePlayerNames.clear();
 		
 		allIds.clear();
 		allNames.clear();
+		allPlayerNames.clear();
 		
 		// Load Datas
 		loadDatas();