Potterfests

Fest Name: Marauders Rarepair Microfics
Links: Tumblr | AO3 Collection Info | Rules | May Prompts
Type of Challenge: Monthly prompt challenge
Description: A monthly prompt challenge for Marauders era rare pairings. Any pairing involving at least one Marauders era character will be accepted as long as it's not one of the banned pairings listed below. You can also submit non-prompt challenge related fics to the appropriate AO3 collection. For more information, see AO3 Collection Info.
Ratings Restrictions: All ratings allowed
Length Restrictions: Ideally under 2000 words. Also accept art and other medium.
Timeline: No official deadline; first challenge begins on May 1.

According to the Community Rules, the following ships will not be accepted:
• Remus/Sirius (Wolfstar)
• James/Lily (Jily)
• James/Regulus (Jegulus)
• Dorcas Meadows/Marlene McKinnon (Dorlene)
• Mary McDonald/Lily (Marylily)
• Evan Rosier/Barty Crouch Jr. (Rosekiller)
• Pandora Lovegood/Lily (Pandalily)

Fest Name: The Strutting Slut Fest
Origin: The Strutting Stag (Discord | Tumblr)
Links: AO3 & Rules | Overview | Prompting Post
Type of Challenge: Non-anonymous prompt fest
Description: A James Potter-centric fic and art fest run by The Strutting Stag Discord server. Every work must include at least two pairings that include James. AI-generated content is not permitted. Prompting is open till March 26.
Ratings Restrictions: All ratings allowed
Length Restrictions:
Fic: Minimum 500 words
Art: None
Timeline:
Prompting Opens: March 6
Prompting Closes: March 26
Claiming Opens: March 27
Claiming Closes: July 20
Works Due: July 27
Posting Begins: July 31

The Strutting Stag is also running the James-centric Stag Microfic prompt challenge every Tuesdays and Fridays on Discord and Tumblr. For more information, see the Pinned Post.

Fest Name: Prongsfoot Reverse Big Bang
Links: Tumblr | AO3 | Rules | Timeline | FAQ | Artist Sign-up
Type of Challenge: Anonymous reverse big bang
Description: A James/Sirius fest. Artists will create a piece of James/Sirius artwork, and writers will claim one of these artwork and write a fic inspired by the artwork they've claimed. Artist sign-up is open till May 8. AI-generated content is not allowed.
Ratings Restrictions: All ratings allowed
Art Requirements: This fest accepts digital art, traditional art, moodboards and comics.
Digital or traditional art: Minimum 1 finished piece
Moodboards: Minimum 10 images
Comics: Minimum 4 panels
Fic Requirement: Minimum 10,000 words. No maximum
Timeline:
Artist sign-up opens: February 15 - May 8
1st artist check-in: March 18 - March 24
2nd artist check-in: April 22 - April 28
Writer sign-up opens: April 29 - May 30
Art due: May 22
Art preview for claiming: May 31
Writers claiming: June 3 - June 5
Pairs announced: June 7 - June 10
1st pair check-in: June 12 - June 16
2nd pair check-in (rough draft 40%): July 22 - July 26
3rd pair check-in (rough draft 75%): August 19 - August 23
Fics due: September 16
Posting: To be announced

Fest Name: Jegulily Week 2023
Links: Tumblr | AO3 & Rules | Prompts
Type of Challenge: Prompt challenge
Description: A week long prompt challenge dedicated to the ship James/Regulus/Lily.
Ratings Restrictions: All ratings allowed
Length Restrictions: None
Timeline: November 5 - 11

Fest Name: Marauders Fest
Links: Tumblr | AO3 | Rules | FAQs | How to get a prompt
Type of Challenge: Prompt fest
Description: A fic and art fest featuring characters from the Marauders era. Send a message to the fest mod to receive a randomly generated prompt: a pairing, a colour and a trope. You can skip a prompt up to three times. Posting is done on AO3.
Ratings Restrictions: All ratings allowed
Length Restrictions: Minimum 500 words. No maximum. Art is also welcome.
Timeline:
Deadline for claiming prompts: October 1
Submission deadline on AO3: November 1

Fest Name: Prongsfoot Fest 2023
Links: Tumblr | AO3 | Rules | Claiming Post
Type of Challenge: Prompt fest
Description: A prompt fest featuring the pairing of James Potter and Sirius Black. Claiming is open till September 20. Self-prompt is allowed.
Ratings Restrictions: All ratings allowed
Length Restrictions:
Fic: Minimum 500 words. No maximum.
Art: None
Timeline:
Prompting Opens: July 1st 5:00 pm GMT
Prompting Closes: July 15th 5:00pm GMT
Claiming Opens: July 17th 5:00pm GMT
Claiming Closes: September 20th 5:00pm GMT
Submissions Due: September 27th 5:00pm GMT
Posting begins: October 8th 5:00pm GMT

Fest Name: Buck Moon 2023
Links: Tumblr | AO3 | Rules | Participation Guidelines | Optional Prompts
Type of Challenge: Prompt challenge and rec event
Description: An event celebrating the pairing Remus/James. There are 2 ways to participate: Create a new Remus/James fanwork and post them on AO3 or Tumblr; or recommend an existing Remus/James fanwork, self promoting encouraged.
Ratings Restrictions: All ratings allowed
Length Restrictions: None. Accepts any medium of any length.
Timeline:
Submit fanworks to AO3 & recs to Tumblr: June 3 - July 4
AO3 collection revealed: July 2
Last day to add works to AO3 collection: July 4 at 11:59pm EDT

Fest Name: Buck Moon 2023
Links: Tumblr | AO3 | Rules | Participation Guidelines | Optional Prompts
Type of Challenge: Prompt challenge and rec event
Description: An event celebrating the pairing Remus/James. There are 2 ways to participate: Create a new Remus/James fanwork and post them on AO3 or Tumblr; or recommend an existing Remus/James fanwork, self promoting encouraged.
Ratings Restrictions: All ratings allowed
Length Restrictions: None. Accepts any medium of any length.
Timeline:
AO3 collection opens: June 3
AO3 collection revealed: July 2
Last day to add work to AO3 collection: July 4 at 11:59pm EDT

Fest Name: Marauders Omegaverse Fest
Links: Tumblr | Rules | FAQ | Claiming Post
Type of Challenge: Non-anonymous prompt fest
Description: A fic and art fest revolving around Marauders-era characters and Omegaverse. Claiming is open till August 15. Each prompt can be claimed multiple times. Self-prompt is allowed.
Ratings Restrictions: All ratings allowed
Length Restrictions:
Fic: Minimum 500 words. No maximum.
Art: None
Timeline:
Prompting: May 10 - May 31
Claiming: May 25 - August 15
Works due: August 20
Posting begins: September 1

Fest Name: Jegulus Microfic
Links: Tumblr | Rules | FAQ | May Prompts
Type of Challenge: Daily prompt challenge
Description: A new daily microfic prompt challenge for James Potter and Regulus Black. A new prompt list will be posted every month.
Ratings Restrictions: All ratings allowed
Length Restrictions: Ideally 50-500 words, but there is no official minimum or maximum word count.
Timeline: Posting begins on May 15

For more HP prompt challenge communities, see this link.