I see that there are a few expansion packs and I saw a video at You Tube that someone
posted about the best three MODS to add to the game (Grim Internals/Rainbow Filter/
Item Assistant)
The three MODS sound like there worth it to add to the game before playing
but is it worth buying any of the expansion packs before I start playing?
At a minimum they give you more items that can drop, also at lower level, some new classes to choose from and some QoL features (and obviously the new content, some of which you could access before finishing the vanilla main campaign).
Personally I’d recommend both expansions, but then what do you expect in the official forum of a game 
Thanks for the reply!
Just to be clear, the expansions are Ashes of Malmouth and Forgotten Gods. The Crucible is not so much an expansion as a separate game mode (attack waves in an arena).
The two loyalist packs are not that important, they are more an option to give the devs some more money as a thank you if you do like the game and in return you get some item skins.
Thanks again! I’ll just get some MODS then!
Most mods require the expansions… the ones you listed are not really mods though, so should be fine