Gonna keep it to things not already mentioned.

Big standalone fangame/total conversion:

• Chronicles of Myrtana: Archolos, built off of Gothic 2. Was my GOTY when it came out, and I consider it better than anything the actual developers released since Gothic 2. I really dig the way it expands the original game's systems, like apprenticeship. I have some complaints about it but it's nothing major, and I overall greatly enjoyed my time with it, planning a new run when the big 2.0 update drops.

Mod packs:

• Morrowind Sharp, it's like Viva New Vegas for Morrowind, I always use it as a base for my own setups, but it's great as is for new players to get a patched, QoL enhanced and face-lifted vanilla-like experience.

Individual mods:

• Global Escalation for Squad - just a huge expansion-sized load of content
• Beautiful Cities of Morrowind, for bringing the game's settlements closer to their concept art, implementing a lot of the new fan-made resources to make places more distinct and detailed while having a clear scope and keeping within vanilla-like territory
• Kenshi Kaizo, touches up and expands the existing content without bloating itself by filling the map with all sorts of new factions of varying quality and lore-adherence
• The Stardew Valley mod that adds a whole bunch of cat skins so I can have my irl cat in the game. And on the topic, SDV Expanded and Ridgeside Village when I just want more Stardew Valley stuff.