Your DRM-Free requirement is hard to account for, because some games may get future DRM-free releases, and console-versions are arguably DRM-Free.
Huniepop has significant gameplay in addition to visual novel portions and an option specifically to be lesbian.
Huniepop 2 will feature much of Huniepop 1, also allowing, presumably, for threesomes. There has been some controversy over a "trap character," named Polly, which is worth keeping an eye on (the dev has made attmepts to placate both sides of the issue, but whether this comes down to Polly being actually female or trans-sexual according to the lore [since the option was added for straight males and lesbians, which makes sense when all other options are female exclusively], has yet to be seen).
Jade Empire has romanceable mechanics with bisexual men and women.
A lesbian couple is in New Vegas, both can be recruited as allies, but they never actually are seen interacting with one another, and both are portrayed surprisingly positive (well, the one is, the other is a tossup on how you view her as she's rather gray). There are hints of MF, FF, and MM relationships in the brothels, as well, although i can't remember if this is available to the player. The "Old World Blues" expansion also features a... well.. female? Whom is portrayed mostly positively, and is even a quest-giver, whom appears to be sexually excitable regardless of one's own sex.
Fallout 3 has a female bisexual character who will "simp" (to use today's vernacular) for the player character if "accepted." Interactions are never sexual, iirc, but she's very clear about her blind and unwarranted devotion.
Vampire the Masquerade: Bloodlines also features the ability to seduce both men and women as "blood dolls," and they respond differently depending on whether the main character is male or female (both male-male and female-female pairings are present). The lore behind "blood dolls" however is more explained in Vampire the Masquerade: Redemption, which isn't as good of a game and i don't recall a similar handling. One of the most prominant characters, while portrayed arguably negatively (not for her sexuality, however, and she's simultaneously portrayed positively) is bisexual. I can't remember if this one other character is bisexual or not, but she would also be fairly prominent.
The Neptunia series prominantly features both lesbian and bisexual female representations in both very positive and also very negative lights. Cyberdimension Neptunia: 4 Goddesses Online does this beautifully (actually discussing issues in a fairly objective manner [they appear to tip-toe around the transgender issue, however], including a negative lesbian character stating that love cannot exist in straight relationships [her and her girlfriend are an obvious allusion to issues among straight couples]), but I cannot confirm whether or not the steam version is DRM-Free, as I have the PS4 version. I highly recommend this game for people looking to use the game as a base to comment on issues, due to the obvious issues that they are not afraid to cover in a fairly light-hearted (such as non-trans people playing as characters of the opposite sex: they appear to cover all angles of this phenomenon). The english dialogue is partially censored, but the differences I've heard between the written english and the Japanese audio seem to tone down the sexuality.
Metal Gear Solid 3, two enemies (one of which later becomes a protagonist in the series) are homosexual males.
Metal Gear Solid: Peacewalker, Naked Snake is revealed to be bisexual, and Kazuhira Miller is revealed to be either gay or bisexual.
In theory, in Metal Gear Solid 5: The Phantom Pain, there is an option to be a lesbian, but whether or not that is the case is difficult to clarify, and major spoilers for the main plot of the game. It's certainly not something that one initially understands, however, and most people playing the game likely do not realize it.
Starfox Command: I forget the details, but I vaguely remember something implicitly happening between Katt Monroe and Krystal, seemingly going mysandrist. I honestly forget the deatails, but i doubt this one is what you're looking for, but it's worth mentioning.
I'm sure Skyrim has been mentioned. The remains of a lesbian couple can be found in The Elder Scrolls III: Morrowind, in the Tribunal expansion. The only reason we're aware of this is because the name of the location, as well as evidence that they were killed by Azura while in the act.
Also, all table-tops naturally feature LGBTQIA+ representation, should such a player be present, and sometimes without.
Carmilla of the Castlevania series is implicitly lesbian (by her source material). The succubus in Castlevania: Lords of Shadows: Mirror of Fate, although an antagonist, is portrayed as bisexual (although evil, i suspect that you're focused more on portrayals for the purpose of condemning LGBTQIA+).
My planned game will, because i have to shill, feature enough freedom to be straight, homosexual, or bisexual, regardless of character's own sex. Although through odd means, transsexuality is planned, as well as transgenderism (however there will be no pronoun support, but you're free to add it), this is the result of consequence, not as an intended purpose. I plan on featuring 2 major NPCs, one of which would be lesbian and another of which is a male bisexual. The former being a gray character (leaning negative, and for sexuality, but due to their representation, not for being a lesbian), the other being HaSatan, himself. Generic "intelligent" NPCs (humans, foocubi, vampires, etc) will have their sexuality randomly generated (and "fluid," as opposed to simply 2 binary choices of whether or not they like men or women), and will all be interactable (except children, which is the one freedom i plan to restrict, for self-preservation reasons). I'm planning on a few odd intelligent NPC types as well as non-intelligent NPC types that could be interacted with in a romantic (for intelligent) and strictly-sexual (for non-intelligent) manner whom are, well, incapable of being male or female, but aren't necessarily "neutral" either (for an example of one, i was consider an intelligent "slime-mold," which inherently must be 2-sexes at the same time, and these could not be defineable as either male or female, due to the nature of slime-molds).
The Witcher 3 features a playable bisexual woman.
I'm sure there are much more in my collection which I don't remember off the top of my head.
Oddly enough, I have yet to see LGBTQIA+ people presented in a negative way in [u[any game (at least for their sexuality: the closest would be Starfox Command).
It's worth mentioning that there is an obvious favoring for lesbian representation, often times anti-male lesbians, implying that this bias is not for the male audience. I can't remember if i revealed the reason for this or not, but a little research on your part might explain it, and it seems like it's up your alley.
osm: Here's hoping this guy'll get banned like the other one here that was running around with all the gay bait stuff.
PS it's LGBTQi+ you heartless cis fascists!!!111
You forgot the A, which is Asexual or "Allies," depending on interpretation, you bigot.
babark: Why is belief in a concept a prerequisite for you to experience a piece of media?
I don't believe in wizards or dragons or time travel (beyond 1s/s) or zombies or uploading consciousness into the cloud, but that doesn't stop me from experiencing media which involves those themes and concepts.
morolf: I don't want to go too much into details (don't want to get perma-banned), but I think promotion of transgenderism as something positive can be harmful, since it might persuade some people who are easily influenced to make choices that are irreversible (drastic surgeries like mastectomies) and which they later regret. With current technology it's just not possible to really change your biological sex. I find pretending otherwise unethical.
And in this regard transgenderism is very different from homosexuality imo.
I'm all for free-speech. I think the bigger issue is not the promotion, but the inability to condemn, as well as the notion that promoting the inverse is also evil. There also appears to be a strong affinity for "corruption fetish" as well.
