What some might call "content". I only add ones that I eagerly follow or think are worthy of recommending, so the ★ system doesn't apply here.

A MegaCollection

Youtube

• ClassicsOfGame: Classic Games
• Highlight Reel: Weekly compilations of game glitches and moments.
• minimme: Super obscure games.
• ThorHighHeels: Odd games. Fantastic aesthetic.
• Nitro Rad: Videogame Youtuber. Does 3D platformers and horror games.
• Atari Archive: History of early videogames, one 2600 release at a time. (Website)
• Ahoy: Various retrospectives on old games. Fantastic style reminiscent of old Atari boxart.
• PandaMonium Reviews Every U.S. Saturn Game: Extremely thourough documentaries.
• Summoning Salt: Documentaries on speedrunning.
• ThaRixer: PS2 speedrun documentaries.
• Maximum: Flash game speedrun histories.
• AsumSaus: Deep dives into Melee.
• decino: Examinations of the mechanics of Doom.
• SiIvaGunner: Many have been fooled by their high-quality videogame rips. (Website) (Bandcamp) (Neocities page, don't know if official)
• RebelTaxi: Videos on animated cartoons and old games. Y2K Aesthetic.
• Zetta: Highlights of Rivals of Aether Workshop mods.
• 4096: Phenomenal transitions.

Tumblr

• Tool Assisted Speedrun Clips (@toolassistedspeedrunclips): No context clips from Tool-Assisted Speedruns.

Blogs and Newsletters

• Legends of Localization: All about video game translation.
• 50 Years of Text Games: Newsletter about text games and interactive fiction. Completed, now with book.
• Read Only Memo: The latest news from the world of emulation.
• The Obscuritory: Lesser-known games.
• Bad Game Hall of Fame: Sincere examinations of bad games.
• Critical Distance: Curated videogame articles and videos.
• Garbage Day: Newsletter about the internet.
• The History Of The Web: Every entry adds to a timeline. Currently inactive.
• 30pin: Online magazine about consumer technology. Currently inactive.

Podcasts

• The Shrieking Shack (Shriekcast): Formerly a critical and funny analysis and re-read on the Harry Potter series that actually holds its feet to the fire. The reason I signed up on Patreon. Completed, also read through Twilight and Midnight Sun. Sometimes drops episodes on other books and movies.
• Homestuck Made This World: Homestuck contextualized and re-read through the lens of its impact. Completed, currently going through bonus episodes (Patreon-locked) and Undertale Lets Play (Youtube). I read along with the unofficial collection[mentioned here]. (Companion Tumblr with fanart mentioned in the show) (Tumblr explorer organized by partisode) (All summaries) (Youtube mirror of all summaries)
• The Content Mines: Behind the curtain of modern internet platforms. Cancelled. Part of Garbage Day (mentioned above). (Substack powered website)
• Bullet Time: A Youtube video essayist and friends explore old mid-tier/obscure FPSes.
• Something Rotten: Violent, disgusting games.

Suggest more in the comments!