Copy-pasting an alternatives list to Steam along with some reasons to use them here:
Playism
>DRM-free and proud of it
>helps out indie developers with debugging, localization and whatnot and works with nipponese and english developers alike
>Japan-based and created by them with good relationships
>responsible for publishing some good indie games (Cave Story, One Way Heroics, Kero Blaster, etc.)
http://playism-games.com/
Gamejolt
>Has their own client (still in beta though but good enough)
>DRM-free
>A shit-ton of indie and passion project games (but basically no curation)
>No known censorship problems so far and overall good-sounding
>established community
https://gamejolt.com/
And of course MangaGamer and JAST for your lewd shit from nippon:
>localizations are improving over time
>they work with the nips closely and are good overall
>also offer physical products for some of their games
>DRM-free
>Staunchly anti-censorship in the case of MG and JAST offered a place for some of the developers getting censored by Valve right now
https://www.mangagamer.com/
https://jastusa.com/
GoG
>Staunchly anti-DRM
>offers some major titles that Steam used to have as exclusive; might be a viable competitor at some point in the future
>acted as a refuge for numerous VNs and small devs during the waifupocalypse
>lots of support for old games
>high-quality curation overall, and is improving over time as they allow more shit in
<not as trustworthy as the other alternatives because of the firing and the way they handle social media
<curation is opaque as all hell and good games get lost in it
They're less recommended now than the others, but still better than using (((Steam))) if you have to.
>Itch.io
>DRM-free
>choose what you pay to the developers (can be up to 100% afaik, ensuring that their actions as a middleman can be limited unless that changes)
>lots of support for indie developers
>no known instances of censorship; unknown if curated at all but presumed not to be
<Lead people in charge of it are known to be pro-censorship, making them not entirely trustworthy, one should be wary and cautious when using them
J-list
>Sells general good from Japan, from food to manga to figs to vidya
>sells adult goods from Japan, little worries about them censoring
>works with publishers like JAST to sell games
>Very pro-Japan; is an importer
https://www.jlist.com/
>Right-Stuf Anime
>Recommended by operationrainfall and other generally good sources
>is an independent distributor and publisher of video and whatnot
>offers vidya options and other shit as well
>no real problems found
https://www.rightstufanime.com
Play-Asia
>Staunchly anti-censorship; even going so far as to mock Sony's censorship policies on their social media platforms
>anti-SJW and pro-GG
>imports everything from adult goods and vidya to other assorted things, overall solid and they're improving all the time with a wide selection
>excellent customer service
>also recommended by oprainfall, nichegamer and numerous other pro-GG and good neutral places; sometimes works with them for giveaways and whatnot
https://www.play-asia.com/