I broke a box of baseball on the site way back in the day. 2011 topps Allen and Ginter. Interesting stuff. Got a cool jack lalaine film cell relic card. From the breaks I've seen of A&G, it has been hit and miss. The designs are cool, but it seems the cards have little value.
Everyone wants Bryce Harper and Steven Strasburg cards so lots flock toward Bowman cards since the is the rookie/prospect division of the baseball realm.
If you want middle of the road, topps lineage and heritage are cool sets that aren't too much more than the base series 1 & 2 sets.
If you want to go bigger, look at Marquee and Triple Threads or Tier 1. Much more $, but nothing says awesome like the chance of getting babe Ruth, Mickey mantle, ect memorobelia cards.
If you want some really off the wall stuff, look at Goodwin Champs. They consider it a baseball product, but it has cards from almost every sport. What other set has famous horse hair samples or dinosaur teeth redemptions and entomology cards with real insects? Go on YouTube and watch some videos of those mail days. Crazy stuff!
I hope this helps. Not much really stacks up to artifacts , etc. they love to go big or go home with baseball products.