Best Gmod Addons?

It's depends for what purpose:

For props: Stacker, Precision Tool and others
For some "magic": Wiremod
For RP: VCMod, M9K/FAS

VCMod has to be my favorite if I had to choose a mod, but gamemode wise I would choose DarkRP but only as a base to recreate what you need.

some of the best addons are printers and bitcoin mining

NUTSCRIPT!The best game mode in Garry`s mod..............

I would generally say my favorite mods are Wiremod, Gbombs, m9k, and gibmod. I wish there were still big mods being made today

For vehicles, use VCMod or Simfphys.
For weapons, use CW 2.0 or TFA.

It's really up to preference.

I believe that the best addons for RP:
WYOZI CAR RADIO - Radio, which is heard by all players near the car
OS X HUD - Minimalistic hud
Elite F4 menu - Minimalist menu.
CUFFS - HANDCUFFS AND HAND TIES - At the moment this addon is the only normal for RP handcuffs.
BLUE'S SLOTS - DOUBLE OR NOTHING - A simple and beautiful casino machine.

VCMOD is a winner for me! Like using both ELS and Main

Simple hitmaker, skatebords, and easy tool animation.

It depends on the situation.

For Props : Precision tool,Stacker tool,No collide tool,Etc.
For Darkrp: Victorious hud,Victorious f4 menu,Donation package,Servergaurd.