The datablock limit is 4096.
The default game uses about 1000 datablocks. This leaves about 3096 datablocks left for add-ons.
An average weapon/item or vehicle uses 10-15 datablocks, even less if they reuse existing datablocks, which many do.
Sounds/music use 1 datablocks, bricks use 1 or 2 each.
There is simply no reason you need that many add-ons.
The solution is to stop downloading and activating every single add-on you see.
The game uses 421 for all the non-addon, non-paint, non-music stuff.
Colorsets use 7 per color. (2 particles, 2 emitters, an explosion, a projectile, and an image)
Music uses 1 datablock per song.
As for add-ons:
Emitters will use 2 for each emitter.
Lights will use 1 for each light.
Sounds will use 1 for each sound.
Bricks will use 1 for each brick.
JVS content bricks can use anywhere between 2 and 8. Though I'm sure all of them have like 5 or 6.
Prints use 0.
Can't quite tell for vehicles because most of them tend to re-use jeep's datablocks, and the jeep and gravity rocket executed with the tank for a combined total of 43. I'm sure a non-default add-ons probably do not reuse other datablocks, so it's safe to assume that all turreted (non-bot) vehicles use about 40. Non-turreted vehicles probably use about 20-30.
A weapon can be as simple as 8 (unless it reuses other datablocks, or lacks emitters), and as complicated as 16. (or more)
So let's say we'll have 5 vehicles and 20 weapons, with one of those overrated 64 color colorsets.
421+448=869
869+125=994
994+240=1234
Now with the default emitters, lights, sounds, music, items, emotes, bricks, and projectiles.
8+9+3+9+8+12+16+8+4+19+8+3+3+3+5+4+9+1+12+15=159
1234+159=1393
So I'm not sure how you can even reach the datablock limit while using a reasonable amount of add-ons. You'd have to be downloading and enabling an abundance (more than you can actually think of using) in order to reach the limit.
Of course, things like TDM and zombies were not included in this calculation, but I'm sure they don't add about 3k datablocks themselves.
