The original chase in Splinterlands was going for the coveted Golf Foil Legendaries when opening packs. In fact, it was due to a GFL that I got pulled into the ecosystem forever. I still remember buy my first 5 packs during Alpha and one of those packs got me a Gold Foil Lord of Darkness which I still have today; it is a critical piece of my Collection on Land producing resources. The rest has been history.
I have had some mixed experiences from the various editions I have since opened hundreds or thousands of packs for. The latest was Escalation and my expectations were low as the amount of packs was not as much as previous editions. However, I did use my Glint to acquire Potions to ensure my chances would improve. Not sure what the expected rate would have been but my own were to get 1 in every 400 packs so at least three. Unpacking 4 was pretty positive so happy to have some ammunition for the upcoming Conflicts next.