When I need to take multiple screenshots and save immediately (instead of pressing PrintScreen + paste), I use this
http://www.michielovertoom.com/software/snapper/

Not sure if it works on all games. I use it more often for screenshots when working with documents rather than games.

If using Steam, you can use its built-in screen capture.

I use Fraps too and never seen a downgrade in image quality, but I save the images as .png format. Maybe you're saving yours as .jpg, which is a lossy format, so it's normal to see some details loss, especially for text.

i still use the old printscreen(if just that screen then alt+n+printscreen), open a image software/paint/etc paste,save as png
if have spare time not in rush or being chased, snipping tool, select area
i've seen other people use other programs, cant remember the name of but i think those require account & somewhat easier to share online(i think)

No. I start with BMP and convert to PNG.

(Linux user here)

I typically use either scrot or import. If it isn't in the right format (or is too big to attach if it's a .png), I use convert to convert it to a better format.

(import and convert are provided by the ImageMagick package, which I believe is installed by default on some distros.)

Fraps has been moribund for a while now, hasn't it?

Most Linux DE's come with their own basic tool for taking screenshots, so that's quite simple.

Xscreenshooter and Gnome Screenshot both use the same shortcuts, but that's just an aside.

I in short, accidentally erased my Windows 10 install so that's no longer an option.

OBS Studio would probably be massive overkill for your needs, but there's ShareX, and LightScreen.
https://getsharex.com/
https://lightscreen.com.ar/

In Windows 8 and later, there's the Gamebar you can use instead, but users have been reporting issues with that.

There's Bandicam. Most of the time I used it to record videos, but I believe it captures good quality images.

Oops! Well, at least this will force you to learn your way around Linux.

I'd already been using Linux since Fedora 25 as a DD.

Thing is, a partition move failed, KDE's spin didn't install right, and I overwrote the intramfs on both drives.

Greenshot works very good for me, especially if I only want to take a screenshot of a portion of the screen.

The Windows Snipping tool.