Something like this

The Compaq I had looked like this (image shamelessly pulled from google):

IIRC it was standard mATX inside, with an SFX form factor power supply.

Pretty much any case from the pentium 1 to 2 era is going to be what was used. I guess theres no real correct case type or style just anything fromm 95 to 2000 ish

I had this one back in the day.
917B

Beige, possibly with grey accents (especially if it is a Compaq or HP). Also, this was about the time when case trim started to really transition from straight, squared-off lines towards more curvy designs, the Compaq case shown in SW-SSG's post being the biggest example. The iMac-inspired explosion of translucent colored case trim didn't really take hold until the tail end of the K6-2 era that I can recall, and the "black is the new beige" phase of case design was still a few years off yet.

Well , My IBM Aptiva with K6-2 333mhz CPU is White with blue accents.

I think generic/bland AT or ATX is typical of that era, doing away with turbo buttons and MHz displays. My K6-2 in '98 was built into a pretty generic ATX case, possibly a Macase (http://www.macase.com/macase/pc-atx.htm), my PII was in a smooth-fronted AOpen HX08, and I recently bought this system - an anonymous AT mid-tower with K6-2 300 original build:

(seller's pic, I've washed it up a bit already)

Also had my eye on an ATX Super 7 machine recently, which was a generic version of the blue/white IBM Aptiva case posted above, but the seller must have deleted the listing already.

K6-2 were budget builds. The authentic case will be a cramped Baby-AT carryover from a 486 or Pentium. Cheap looking, kind of dirty, maybe some blood stains, not sure if they were turning yellow yet.

After some heat issues, there will be an ugly hole cut in the front of the case with a fan bringing more air to the CPU. Okay maybe that was just me.

I think I had the same case JidaiGeki posted in that picture.

I contacted AMD back in the day and they sent me some AMD k6 badges for FREE.
I still have some somewhere.