I'm on the list for several of the oddball blankets and shawls and am trying to determine which stitches to use. I know that some pull in much more so than other and wonder how one can tell which ones do so the most.

There's no exact answer, but the stitches that don't pull in much are:

Garter
Stockinette
Lace
Any knit/purl pattern like moss, seed, or basketweave

Some stitches that do pull in are:

Any kind of ribbing

Any kind of cable

That's about it.