The Expanse series has Naomi Nagata, Avasarala, Bobbie Draper, and Drummer (among others)

The Revelation Space trilogy by Alastair Reynolds has the badass Ilia Volyova (cyborg space pirate; it makes sense in context lol) as a main character (not primary protagonist though) in the first two books and Ana Khouri (ex-military/assassin) is the primary protagonist in the second two (and major character in the first).

Some of Reynolds’s other works also have strong female protagonists as well (e.g. Pushing Ice and the whole Revenger series). House of Suns is one of my favorites, and there are two protagonists, male and female, and have equal spotlight throughout.

Both of those are hard sci-fi, so hopefully that’s your jam.

Try out the Wayfarer’s series! Becky Chambers is amazing. Her books are wholesome and character focused, and give you a great feel of what it would be like living in that setting.

I also really like Brandon Sanderson’s Cytoverse. It’s a fantastic adventure that will keep surpsing you, but it is YA, so be ready for a little silliness.

Parable of the Sower by Octavia Butler.

• Silo series by Hugh Howie
• Shatter Me by Tahereh Mafi (Young adult dystopian scifi)
• Across the Universe by Beth Revis (Young adult)
• Bird Box by Josh Malerman (apocalyptic thriller)
• Mistborn by Brandon Sanderson (fantasy, not scifi, but I’m digging up stuff from when I used to read more prolifically)
• Revelation Space series by Alastair Reynolds. I read this so long ago, and I feel like their were some great female characters, but I can’t remember if any were the protagonist. Each novel shifts around.

The Space Between Worlds vy Micaiah Johnson

A Half-Built Garden by Ruthanna Emrys

Pretty much anything by Octavia Butler.

Gideon the Ninth?

Takes like 5 chapters for it to find it’s feet but it’s lesbian necromancers and swordfighters in space with a very snarky point of veiw character.

It’s kind of more scifi fantasy but a good time.

Pretty much anything by Cherie Priest, the Clockwork Century books are great!

Xenobiologist Kira Navárez in To Sleep In A Sea Of Stars might not win feminist awards, but I really liked her, the world building and the story. IIRC, it was relatively clean of overly sexist BS.

Echoing what others have already said here: The Expanse. The depth and quality of pretty much all the main characters is great. And there are several fantastic female characters who are strong, smart, and wonderfully written.

The “Broken Earth” series by N.K Jemesin

First book

Sassinak by Anne McCaffrey was pretty good.

I thought YT was a well written character in Snow Crash. She took no shit from anyone.

I see lots of good picks here, a few of my favourites books mentioned… I love The Expanse in particular, but “Pushing Ice” by Alastair Reynolds had a better focus on complex female characters.

The Steerswoman series by Rosemary Kirstein, and the Merchant Princes series by Charles Stross—both series that may not seem like sci-fi at first, but become increasingly so as they progress.

The Iron Widow by Xiran Jay Zhao. Think Neon Genesis Evangelion X Female Rage X Chinese History. It’s by no means a perfect book, but it’s entertaining, the premise is very interesting and the character work is quite good!