YMMV depending on country. In the US you can find at least a handful of named anarchist organizations in any given state. Many anarchist or libertarian organizations keep it on the DL for a multitude of reasons. You may have better luck finding groups under the monikers of communalist, x or y federation, social ecologist, or just plain ole socialist. Mutual aid networks, food not bombs chapters, and IWW chapters are other spaces a lot of anarchists occupy. Many anarchists still stick to affinity groups and the like as well so, while they may be out there and active, it’s likely you’ll never hear about them. Further muddying the waters there’s also the concept of social insertion where anarchists support local movements and encourage (but don’t attempt to force) the popular movement to develop in a more libertarian fashion. Some big names in the libertarian milieu in the US are the symbiosis network and moneyless society. The black rose anarchist federation is another one I’ve seen around.

That said, it’s still hard to find other anarchists in a lot of areas. I’ve been on the hunt for a while and haven’t had any luck in my area. The closest I have is a food not bombs chapter in my city but they’re all a bunch of zionist soc-dems. 🤷 They do good work but I don’t want to be the only anarchist in the group haha. I’ll be handing out zines and fliers at the pride parade in a few weeks in the hopes of starting a reading group and hopefully an explicitly anarchist org in my city