I didn't see anyone start it yet, but since there was discussions about it on the Discord server, I figured it was time to start one! I'll copy-paste most information from Derpi, since they'll apply here, and update any links to Manebooru ones!
We are now opening the ability to request OC tag descriptions to anyone, provided they follow the requirements below. It's important to know, before making a request, that OC tags are not owned by anyone. They are not verified like artist tags are. They are just for what we hope is helpful information. If two OCs have the same name, they can share the same tag, like OC:Jasmine.
→ 1. List the Character's name. Use a relative link. If you don't know how, just copy and paste the text below and replace anon or cloudy canvas with the name you're requesting a description for:
Typing "oc:anon":/tags/oc-colon-anon gives you oc:anon
If the character has a space in their name, replace it with a plus sign: "oc:cloudy canvas":/tags/oc-colon-cloudy+canvas becomes oc:cloudy canvas
This link must be entirely in lowercase; the link won't work otherwise.
→ 2. List the creator's Derpibooru account, if they have one. The easiest way to find this is just to click their artist tag and see if there's an associated user. You can link the account in the post the same way as you do the OC name in step 1:
Typing "NorthernDawnArt":/profiles/NorthernDawnArt creates a link to the account: NorthernDawnArt. Note that the account names are case-sensitive!
If they don't have an account (or it's not public), include a link to the creator's primary website, such as a DeviantArt, Tumblr, Furaffinity, Patreon, or Pixiv acccount. If you know of a website where you can find out more about the OC (such as a Tumblr "Ask" page) list that as well. If any of these outside links are NSFW, please mention that they are.
If the creator is truly unknown, or a collaboration, state that. Some OCs originated on 4chan's /mlp/ board and are collaborations and we list them as such.
→ 3. List the character's species and (primary) sex. Use whatever binary or nonbinary terms you wish. If they often appear as a R63 version, or if they're usually in human or anthro form, feel free to mention it.
→ 4. Description: Write one or two lines describing their personality, hobbies, job, physical traits, sexual orientation, or other characteristics that are noteworthy. This must be safe-rated (even if a majority of the pictures of the character are not), so be creative. If they are involved somehow (employed by, related to, lover of, neighbors of, etc.) with another character (canon or OC), mention it. Please link any other related OC in the same manner as the link in step 1.
→ 5. Image Link a safe-rated image of the character that is posted on Derpibooru. Link using the >>123456s format. Images where they are solo and in pony form (for anthros) are greatly preferred.
Any requests going forward that don't meet these criteria will be rejected, but we'll try to state why so that you can fix it.