Exactly what the title says, I'm compiling a list of sites that allow loli, shota, and cub context. If there is something I've missed, please let me know!

InkBunny - Cub only, no NSFW human art allowed, but you're free to link to it off site as a thumbnail. Very active community, lax rules. Highly recommended if you're really into cub stuff.

Pixiv - Allows everything so long as it's drawn. Highly recommended. The only major drawback is that all NSFW has to be censored, due to Japanese law. However, a little black bar is a small price to pay. Site is mostly a Japanese userbase, however the site has become a lot more easy to use for foreigners. Not much of a community per se, as there's not journal features and comments are mostly "nice art", etc. They do have communities, but most are in Japanese so I have no idea how active they are. That said, I cannot recommend this site enough; it's where I get most of my hentai from.

Pawoo - Allows everything drawn and has the exact same rules as Pixiv, since they own this site. It's a Mastodon instance so it works a little bit like Twitter. Don't use this one as much, so I can't speak to how active it is.

Baraag - Allows everything drawn. It's got a small but very friendly and welcoming community. I highly recommend this site and wish to see it grow. It's also a Mastodon instance so it works similar to Twitter.

HicceArs - This site allows everything as far as I know, and you can add a payment method for some of your galleries. I don't know much else about this site so I can't speak for it's community or anything.

Pomf.tv - A streaming site similar to Twitch that allows loli/shota/cub content.

Telegram - A messenger application; somewhat similar to Discord but you host channels rather than an entire server. Unless you upload an image as a file download, then they will be uploaded in lower quality. Hit and miss, really.