Are the ones I know about being active, out of personal experience with them (me being in Entropy)
There's also The Qorit Network, House Kerstas, House Kyniska that I've heard or seen around, but unsure about their overall activity so maaaaybe reaching out to their members would be needed if those options sound good. No idea how the rest of them are, as many guilds do keep a "bubbled" approach and just bump their threads only when they want to recruit a few people before "sealing off" again.
Of course, it also depends what you mean by "active". With the current population of ToR many guilds are active but with far less people online on some days / some hours.