I post a lot of links to preorders, in stocks, and deals throughout the week on Twitter. This page will just collect most of the preorders or in stocks, if still available, and put them all into one easy list for weekly reference, in case you missed anything:
Marvel Legends:

Hasbro Marvel Legends Falcon and The Winter Soldier John F. Walker Walmart Exclusive ($22.99)


Marvel Legends Spider-Man Retro Carded Web-Man:
Amazon ($22.99)
Entertainment Earth ($22.99)
BBTS ($24.99)
Best Buy ($22.99)
Marvel:

Sentinel Fighting Armor Deadpool BBTS US exclusive ($99.99)
Star Wars:

Star Wars Black 6″ Kenner Obi Wan Amazon Exclusive is back in stock ($19.99)
Mezco:

Mezco One:12 Collective Wolverine Deluxe Steelbox Edition:
BBTS ($155.00)
Entertainment Earth ($155.00)
Mezco ($155.00)
NECA:

NECA American Werewolf in London Ultimate Nightmare Demon:
BBTS ($32.99)
Entertainment Earth ($32.99)
Storm Collectibles:

Storm Collectibles Street Fighter Evil Ryu:
BBTS ($89.99)
Entertainment Earth ($89.99)
Transformers:

Transformers Generations Selects Titan Class Black Zarak:
Entertainment Earth ($159.99)
BBTS ($159.99)
Hasbro Pulse ($159.99)

Transformers Optimus Prime Modern Icons Replica Helmet GameStop Exclusive ($129.99)

Flame Toys Windblade Furai Model Kit:
Amazon ($50.00)
Entertainment Earth ($49.99)
BBTS ($49.99)
McFarlane Toys:

McFarlane Toys DC Multiverse Target Exclusive Helmeted Wonder Woman ($19.99)
- Hasbro: Pulse Fan Fest Preorder Rundown - April 10, 2021
- Hasbro: Ghostbusters Afterlife Mini-Puft Surprise Toys Revealed - April 8, 2021
- Weekly Action Figure Preorder Rundown – April 5 – 8, 2021 - April 8, 2021