So, so far, we've got...
1. Grandparents: to Pilot
2. Reese Cooks: to Krelboyne Girl
3. Mini-Bike: to previous ep
4. Monkey: to Dewey's Dog
5. Clip Show 2: to "Rollerskates" and "High School Play"
6. Dewey's Special Class: to Pilot
7. Victors other family: to Baby(2)
8. Stilts: to Red Dress
I'm honestly shocked they didn't do more of these. I actually remember, while watching the show, actually hoping they'd do some. Sadly, they hardly ever did.
Thankfully, though, they're all over "The Middle". (To name a few: the disneyworld trip, Frankie taking up beading, the lime jello salad, the backyard wedding, taking care of Frankie's sister's house...not to mention the various story arcs!)