Returning to the game: q about servers and mods

[Dodo_Dead_As_A]

Hello all! I'm returning to the game after a couple of year's absence, and have now patched my game all the way to 4.11m.

I'm first and foremost an online player, so I'm eager to get back to the servers. But as I've understood, the online community is now fragmented due to different servers demanding different modpacks.

I have no idea at all about the mods. I used to fly in the most realistic servers, such as Warclouds and Spit vs 109. So, which mods should I get to fly in the more realistic servers and where to get them?