As I've done quite a bit of research into this following successfully repairing my 5500 I thought I'd post my cooling/fan replacement and upgrade findings here and let others contribute as well.

Stock Fan/Cooling replacements/fixes
The stock AAVID cooler/fan combo seems to work adequately, but by this time in the cards life most have bad fan bearings. Finding the fan on it's own(MODEL 1447122) in new shape is near impossible so most of the time this is not a viable solution.

• Currently there is NOS of the fan and heatsink on ebay for $8.95!
• A 2 wire version of the fan is on ebay as well. Has the same part number and I suspect the original 3pin pigtail could be soldered right on the board of these fans as they have the same part numbers. The seller says it is seller refurbished, so take that with a grain of salt. Might be worth inquiring for more info if you are interested in this as a replacement.
• One fix people seem to suggest doing on the German VoodooAlert forums is to replace the bearing itself. Sourcing this seems like more time/cost than the fan itself is worth, but if it's something that interests you or you want to rebuild/grease the fan follow the guide in the link below.
  https://www.voodooalert.de/board/forum/index. … r-lagerwechsel/
• A decent aftermarket replacement is the SUNON KD0504PEB3. It's 5V and the same 7mm thickness, but has no signal wire. There are conflicting reports on if the Voodoo card even uses the RPM signal if it is available, but general consensus is that it's okay to run a fan without. If you do get this fan (or any other non original) you'll need to affix a JST 3pin 2.0mm spacing connector to have it plug and play on the 5500. This can be done with simple soldering to the old fan plugs or by tracking down the pins and plastic JST shell and crimping to the new fan wires.
• If you have the space for a full 10mm thick fan and/or don't mind having a brown fan mounted the Noctua NF A4x10 5V is probably the quietest replacement.
  https://extreme.pcgameshardware.de/casemods/4 … fx-casemod.html

Aftermarket coolers
Say you want to remove the factory heatsinks because thermal paste or modern thermal adhesive tape probably will conduct heat better. Follow the video below for the best method to remove the heatsink. I found you didn't need to put that much freeze spray on to adequately chill the chips. You can also use Compressed Air cans if you hold them upside down for the same effect of freezing.
https://www.youtube.com/watch?v=5hB4jOCHLHc

Once you have the coolers off you'll need to begin the arduous process of removing any residual glue that did not come up w/ the heatsink. Isopropyl Alcohol and a qtip/rag are you best bet. It'll take time and lots of elbow grease to get all the hardened glue off.
The next thing to address is that most aftermarket coolers use a hole spacing of 55mm or 59mm. The Voodoo 5 5500 has a non-standard spacing of 57mm. You can usually file out the holes a bit to allow push pins to fit or if your cooler has rubber pins you can just pull those through and the flex will work fine with the 2mm difference.

Titan TTC-CSC03E

• https://www.titan-cd.com/en/product/12V-DC-Ch … C03-Series.html
• Closest to stock, but uses the mounting holes instead of adhesive to affix the heatsink. Can reuse the original fans w/ these to keep 5v compatibility and stock look.
  

Vantec CCB-A1C or CCB-A1A
Another set of coolers that most people work well is the CCB-A1C and the CCB-A1A.

• The CCB-A1C is copper and has ball bearing fans.
• The CCB-A1A is red anodized aluminum and has sleeve bearing fans.
• Both fit on the Voodoo 5 5500 w/ out and spacing issues from the capacitors being nearby as shown in the 3Dfxzone.it thread
• https://www.3dfxzone.it/enboard/topic.asp?TOPIC_ID=3068
• The fans can be run at 12v or 5v according to posters.
  

Titan CUV1AB/ CUV2AB/CUV4AB

• These work well for cooling the VSA-100s. The 2nd VSA is a tighter fitment due to the capacitors being a few mm closer, but supposedly can be made to fit w/ adjustment on its positioning in relation to the clip. Was referenced as used in the PC Games Hardware article.
• https://www.pcgameshardware.de/3dfx-Voodoo-Ha … pecial-1246582/
  
• Image of one mounted on a 5500
  https://i.imgur.com/Z3KSoic.jpg