Bloons TD 6 is an absolutely wonderful family-friendly Tower Defense game, and if you don't own it already you can grab it free on Epic Games and it works great on Linux.
Kingdom Eighties is at least the 4th game in the series and it's a bit of a standalone spin-off, with a rather different setting compared with previous entries.
Dwerve is an action-adventure with tower defense that released back in May, and they have a major update out now adding in a whole new mode more like classic tower defense games.
Dome Keeper is one of my favourite indie releases this year, blending together casual underground mining with frantic base-defence and a new update just rolled out making it even more interesting.
Lumencraft is a really interesting game that blends together elements of tower-defense, base-building, mining and a little Deep Rock Galactic in a top-down view. A big new release is out now and it's Steam Deck Verified with Native Linux support.
Lumencraft is a brand new release from developer 2Dynamic Games that is going to suck up far too much of my time, and might be a new favourite run blast through on my Steam Deck.
Stepping slightly out of my comfort zone recently to try something different, I picked up a copy of Bloons TD 6 and I think I now may need help to tear myself away from it.
With maps that advance and grow as you play through allowing you to place down more towers and change your tactics, Warstone TD from Battlecruiser Games is now available natively on Linux.