Hey Lykane! I know of a couple of reroll guilds that I’m pretty sure are still going.
And I’m sure I’ve seen posts for another one, but can’t find them at the mo.
Alternatively, if you’d consider joining an established social/raiding guild then our active, chilled out guild on Magtheridon server horde side could be a decent fit. We’re not a reroll guild, but we welcome people of any level so if you want to start fresh that’s totally cool and we tend to have people levelling alts/rerolling on our server so there may be people to level with.
With regard to raiding, we raid normal and heroic and don’t drop our normal raids half way through a tier; they’re always there for new/returning raiders or alts to get into the swing of raiding, gear up and have fun with guildies!
We also run other content together, like M+ dungeons, PvP, older content for mog/mounts/achievements etc. We have a Discord server so there is always someone to chat to on there or in game 
If you’re interested and would like to find out more, hit me up on Discord (Tea003#8087) or BNet (Tea003#2501) for a chat! 