My Vita Is Yuri

Mostly or completely yuri VNs:

A Little Lily Princess - multiple options
Amaranto - multiple options
Aoishiro - multiple options
Asphyxia - more about sad gay angst than actual dating
ATOM GRRL - 18+ option
Blackberry Honey - 18+ option
Black Closet - multiple options
Blossoms Bloom Brightest - multiple options, this is the free version of the commercial game Galaxy Girls, which has an extra route and optional H-scenes.
Ecchi Sketch - multiple options
Flowers - multiple options
Hanahira -
Highway Blossoms - 18+ option
Kindred Spirits - multiple couples but no choice who dates who
Ladykiller In A Bind - 18+, multiple options
Lilium Triangle - 18+
Lonely Yuri -
Love is Strange - free, multiple options
Love, Guitars, and the Nashville Skyline - 18+ option
Love Ribbon - 18+ option
Mira's Magical Mishap - Free
Mutiny! - 18+ option, multiple options
Ne No Kami -The Two Princess Knights of Tokyo- 18+ option
Negligee - 18+ option, multiple options
Nurse Love Addiction - multiple options
The Reject Demon Toko -
Rising Angels: Hope - Has multiple routes
Sacrament of the Zodiac - 18+
The Sad Story of Emmeline Burns - Free
Sakura Dungeon - 18+ option
Sakura Fantasy, Gamer, Cupid, maybe some others, all 18+ options
SeaBed -
Seven Days With The Ghost - 18+, multiple options
The Shadows of Pygmalion - multiple options
Sono Hanabira series in general - Each game is about a single couple. The games tend to be largely about schoolgirl sex and not a lot of plot but they supposedly get better as they go along and many of them have translation patches. There's also a non-H entry in the series, "Remembering How we Met" which is on Steam.
Sono Hanabira (A Kiss for the Petals) - New Generation - 18+, multiple couples but no choice who to date
Sono Hanabira Maidens of Michael - 18+ option, multiple couples but no choice who to date
The Stargazers - 18+ option
Starlight Vega - multiple routes
Sweet Fantasy - 18+ option
Syrup and the Ultimate Sweet - Free, multiple options
Twin Blue Moons - multiple options
A Wild Catgirl Appears - multiple options


VNs with some yuri but not completely:

<3 - free
A Foretold Affair
Airis - free
Amber's Magic Shop - multiple options
Analogue: A Hate Story + Hate Plus - multiple options
April was a Fool - free
Astoria: Fate's Kiss / Labyrinths of Astoria
Backstage Pass
Blue Rose
Brilliant Shadows
Catch Canvas - multiple options
C14 Dating
Cute Demon Crashers (free, short, 18+)
Dahlia (18+)
England Exchange - multiple options
Eternal Hour: Golden Hour - 18+ option
Fate/EXTELLA
Fatal Hearts
Gangsters in Love
Happy Campers
Heileen 3 - multiple options
Hustle Cat - multiple options
Ghosts of Miami - multiple options
Katahane
The Letter
Long Live The Queen - not really a dating game but there are multiple yuri pairings possible
Longstory - multiple options
Loren the Amazon Princess - multiple options
Love and Order
Maid with Perfection
Magical Diary - multiple options
Planet Stronghold
Quantum Conscience
Revolutionary Girl Utena: Someday My Revolution Will Come - multiple options (Saturn game)
Rising Angels: Reborn - free
Roommates
Queen of Thieves - multiple options
Seasons of the Wolf
Seduce Me the Otome Game - multiple options, free
Serafina's Crown / Serafina's Saga
The Seven Districts of Sin: The Tail Makes the Fox - multiple options
Seven Kingdoms: The Princess Problem - multiple options (in progress, but playable demo)
Soul Set - multiple options
Spirited Heart - multiple options if you buy the yuri side
Subahibi (18+)
Sweet Volley High - multiple options but they may end badly (also has 18+ version)
Sword of Asumi - multiple options


Short free games:

Natsu no Hi no Resonance
Pizz'amore (yuri optional)
Romance Detective
Starlit Flowers
Taarradhin (yuri optional)
Tunnel Vision
Witch/Knight
Green Eyed Monster
Helena's Flowers
Witchwood Academy
First Kiss at a Spooky Soiree (yuri optional)
Sugar's Delight - 18+