There are more than i can count, my steam library is filled with them. And i've come to the grim realization that i cannot clean this backlog ever. So instead of thinking about it and making myself feel bad about it, i just accepted i'll never gonna play them and just play whatever i wanna play at any time.
Only exception to this; as a hardcore lotr fan, i'll always regret not being able to play shadow of war. Because i already played it more than once by playing batman games and madmax and shadow of mordor. Because the gameplay mechanics are almost same except atmosphere of the those games.
Mount and Blade. It took of itself just fine, so good that they even released its sequel, no argument there.
But i've never seen some other developer team trying to do the same not even in different setting. ONLY thing i could think of is that other games copied mount and blade style map movement in games like spaz 2 or starsector. Or some others directly copied combat section of it like those multiplayer-only, gunpowder & musket games that I see on youtube, can't remember their name, there are few of them. One of them even was direct standalone mod version of mount and blade iirc.
Only one i know is: Freeman guerilla warfare and it tried to do the same on both accounts with firearms but failed miserably. And now there is some other project on early access, total conflict or something with the same concept but it's on early access so i don't how it will turn out yet.
To this day it's still amazing to me that this type of gameplay loop in mount and blade is not copied and applied to other games by developers. I dont think the game is that niche, not by a large margin.