Tier 8s I have or have played:
IS-3 - Win tank. Get this if you don't have it already.
KV-4 - Blah. Not worth it, especially with gold shells readily available these days.
T-44 - s'alright. I have a Type 5 though, which is basically better in almost every single way.
ISU-152 - most fun TD, regularly got in excess of 5k damage with it.
BL-10 is one of the best guns in the game.
Tiger II - Win tank. Can't understand why you sold yours.
VK4502A - decent fun, lacks pen but it usable. Sold mine as I generally played my tiger II more and enjoyed it more.
Panther II - great fun. Mobility and armour that can sometimes work mixed with the 88L71 makes for a very fun combo.
Ferdi - decent to start, epic once you get the 128. Armour can be useful, but too many people know the weakspots and gold ammo negates the rest lots of the time. I reckon JPII is probably the better tank just because the mobility is so useful.
Pershing - my fave tier 8 medium. mobile, accurate, excellent hull down. You will want this.
T32 - Its a T29 with better hull armour, better mobility, better turret armour - it can bounce most things even on the side of its turret (once upgraded at least)! Painful stock turret though. Get this.
AMX13 90 - fun fun fun fun fun. Autoloader 90mm in a very small package. I'm sure you've seen this destroy many many things.
AMX50 100 - Also very fun, you have the best
AP pen at tier 8 (excluding TDs), incredible burst damage and great mobility. No armour, and reloading the clip is loooong, but still very fun.
Centurion MkI - Haven't played this too much, but a hull down beast. Great pen, decent
RoF, shame about the alpha. Good turret front, but very weak hull and sides. Mobile sniper basically.
That pretty much summarises my thoughts on the non premium tier 8s I own or have owned.