Just a selection of a few off the the top of my head that I've personally thrown a lot:
A domey 173 TP mega pop top mega pearly ice blue king. The DD Chasing the chains van made a nearly impromptu stop at my local course and hosted a small doubles tournament and my buddy spotted some nice kings. He got the coolest white TP double stamp but I snagged this one and didn't know what to expect because the two flat kings I threw in the past were crazy understable. Too many throws to count later and it is one of my favorite flyers of all time. Brand new it only wanted to turn a little on a near full power shot but over the season I threw it constantly and it was, to my surprise, clearly my farthest flying disc though my havocs that I had already owned for a season were close. This disc was truly a gem for me and gets the number 1 nod of my list. I learned a whole lot with this disc. Honorable mention my top top 171 pink opto havoc with a green sparkle stamp which was very similar to my king yet quite clearly less preferable.
A 175 champ groove that my buddy gave me. Most grooves I've encountered in the past were very overstable with heavy flashing but this one has no flashing and I threw it just over 500ft flat ground a couple times this year. So comfy in hand, especially for it's rim width, and it just flies like a dream. Deserves absolutely 0% of the ignorance it receives, what a perfect disc.
159 domey, stiff blizzard boss. I bought it in a disc store on a trip for fun planning on never bagging it but it shocked me. I picked this one by comparing plh with a heavy star boss in the shop that felt "normal" to me, my blizzard had the same plh. This disc was so much more overstable than I imagined it would be even though the star boss felt overstable to me in the store. This disc taught me a few interesting things about disc density. It really exceeded my expectations for the capabilities of an overstable disc of any kind.
179 DX roc. My first roc, only a little waxy but still very grippy and plenty stiff. Started off almost but not quite wasp overstable and wore in soo nicely into a perfect disc for straight shots and eventually turnovers. This disc really helped me appreciate turning straight flying discs, beads, classic designs, and even more so dome, and base plastic! Where as before hand I didn't rate any of these characteristics highly. Now I absolutely love all of these qualities. I never liked the feel of this disc in power grip but I just didn't care frankly, it flew so nicely.
Pink 178 Z Comet. I bought it years ago after reading about it on these forums and wow was everyone right. A domey, slow midrange that doesn't start off very understable and wears gradually into a perfect understable midrange. Just too, too, too fun to throw and to watch slowly glide.
First Run 180 Z Meteor. My personal favorite. Same stability as my comet but quite noticeably faster. Yet to my great surprise I actually prefer it for most of the same shots. My ability to control this disc so very well and so naturally totally shocked me and I couldn't believe that I prefer it to my beat rocs and my comets so clearly. Nuff said really...just my absolute admiration and chemistry with this disc still surprises me.
My first two zones. Both marked 172 but actually slightly overweight, very puddle topped. One ESP and one stiff Cryztal. I haven't bagged them for a very long time but they shocked me in a couple ways. One way was comfort, maybe the most comfy premium plastic disc I've ever gripped in fan grip and especially in my forehand grip. Another was just how nasty overstable they were. I had thrown flx and limited edition z drones in the past but these were both clearly more overstable than any drone I had thrown at the time (not the case anymore). I mean just total meathooks. I had thrown more overstable discs than these before obviously, but I just wasn't ready for these.
A few other's come to mind. My first buzzz (Z, still throw it!), a wonderfully skippy nukeos, an awesome champ roadrunner, my first few teebirds (flat, domey, champ, star, etc. etc.), a few Legacy protege clutches, but I could go on even longer. I wonder what disc will amaze me next.