Honestly the best tower defense games are still Warcraft 3 custom maps, which is getting a refresh with Reforged. I'd recommend YouTD personally.

There are custom game modes for Dota 2 and some of those are pretty good tower defense games.

How can I find these?

Install free dota2 and goto arcade on the menu.

I spent so many hours playing Wintermaul back in the day.

I miss the old model for games where you simply pay one (albeit higher) price and get everything.

There are still plenty of games coming out at 15-20 dollars/euro where you get full access to the game, and ongoing development (which you did not have in the "old model"). Plenty of these games have additional content more akin to an expansion pack or even standalone game for reasonable prices.

You can also now find many games where you experience the full game for free, and you can spend a small sum on cosmetics. Again, going back to the old model, those games didn't have 7/8/9/10 different skins available for each player.

As much as the battlefront/fallout 76 style games are getting bad press, in my opinion it's never been a better time to be a gamer.

On Android, I play a lot of infinitode, which is totally ad free and has the best upgrade tree I've seen in any game ever. It's wonderful.

What do you mean complete? Like you thought it ended too early or what?

One of my favorite tower defenses is Sanctum, on the PC. It's a tower defense with casual FPS elements. (Its sequel I didn't like as much, it's more the other way around as an FPS with casual tower defense elements.)

They felt like an unfinished product, don't remember why.

Is Sanctum fun to play with friends? I'm thorn between buying a single key (3 euros) or four keys (7 euros) on steam.

Sanctum wasn't much fun after a few levels. We ended up playing Dungeon Defenders instead. Still do now and then, great fun with the whole family. Just don't buy Dungeon Defenders 2, it's not as good and very buggy.

If you've got friends I think it's worthwhile, I played most maps either solo or with one friend, occasionally we got a full group too.

I downloaded dungeon warfare (a suggestion from another comment chain) and it doesn't have ads or p2w elements. It was 3 eur in the Android play store.

I really love Radiant Defense, by Hexage [1]. Great gameplay, good art, charming storyline, and you can pay for a full version and there are zero ads.

[1]: http://www.hexage.net/defense/index.html

Check out Dungeon Warfare: https://store.steampowered.com/app/355980/Dungeon_Warfare/

defense grid 1 and 2

Seconded! I love those games. The dialog is cheesy, but in a deliberate and non-obnoxious way. I just wish there was an easy way to wipe away all of my progress in those games and start anew, so I can play another clean play through. I've read some tutorials about how to wipe game data, but it always comes back via Steam cloud (unless I disable cloud sync for that game, but then I cannot play it across PCs). Frowny face.

Definitely. I played the first one to death. And it had a plot!

You can try Dungeons of the Endless, Amplitude Studio's refreshing mashup of dungeon crawling and tower defense.

Thank you, it looks amazing and it's on sale in Steam

Checkout Gemcraft on Steam.