Not all add-ons use the same ammount of datablocks. For example, weapons use a lot of them while bricks use 1 and scripts use 0.
If you really want to, you can scroll up in the console after starting a server, until you reach the part where it is executing all the add-ons.
Executing an add-on is like a "block" of text in the console:
Loading Add-On: Emote_Alarm (CRC:1385772704)
Executing Add-Ons/Emote_Alarm/server.cs.
Executing Add-Ons/Emote_Alarm/emote_alarm.cs.
5 datablocks added.
The last line tells you how many datablocks each add-on uses.
Figure out those ones that use a ton of them and make sure that you really need them.
You can have a total of 4092 datablocks.