Depends on what you like. From technic modpacks I really like Tekkit, so I would recommends newer versions of Tekkit as I find them simpler than other technic modpacks. For adventuring: RLCraft and Tale of Adventures. RLCraft is popular and very deadly. I had fun with it for multiple weeks and Tale of Adventures is a lot less deadly but not as fun. I mostly played it because of nostalgia, but if you enjoy exploring medieval vibes it is fun for a few days. There is many many more, but I have not dived into those.