NuMetalManiak

Megawad releases of 2021 so far (dates are idgames releases):

Refracted Reality (6/12)

Half Moon (6/9)
GOTTAGOFAST (5/30)

Abyssal Speedmapping Session 54: dead.ass (5/30)
Doom 2 In Spain Only (5/15)
Imperfect Hatred (5/14)
Short Maps for Short People 3 (4/24)
Gridlock 64 (4/24)
Destroy Hell (4/23)
Micro-Slaughter Community Project (4/23)

Abyssal Speedmapping Session 53 (4/15)
Project Unity (4/12)

Tenth Gear (4/11)
Plutonia 7: Going to the Hell (4/3)

Clandestine Castle Crashing (3/15)

Abyssal Speedmapping Session 52 (3/15)
Bourgeois Megawad (3/8)
Haunting Outbreak (2/27)

DOOM: Damnation (2/14)

Pandemonium Speed Maps Vol 1 (2/6)
The 128kb mapping extravagant "challenge" (1/31)

3x3 (1/31)

DBP31: Santa's Outback Bender (1/31)

Doomworld Mega Project 2018 (1/31)
Hellevator (1/24)

Abyssal Speedmapping Session 50 (1/16)
The UnMaking (1/1)
Switcheroom 2 (1/1)

also including non-idgames releases and megawads in beta.

Tarnsman's Projectile Hell

Gates of Death

Haunting Outbreak 2
ASCENSIA

About 33 so far, and I know I'm probably missing a few, but this year of the megawad might beat 2020. April was a month of releases for sure.