Top of the page recommendation:
Tokyo Jungle (PlayStation Mobile)
Hot Shots Shorties is separated into four game files, even if you buy this bundle.
Hot Shots Tennis: Get A Grip is worth more than $15, at least to me.
I suck at the golf games, so I can't answer the last question.
You'd probably have to drop a few hundred dollars to get all of the .hack games now.
Tokyo Jungle (PlayStation Mobile)
I feel qualified to answer most of this:Are the PSP Hot Shots worth the price? Shorties look like a fun distraction but while reading the old OT people mentioned that they take four separate entries that you need to load up to play specific games. Have they changed that recently?
Tennis looks fun but is it worth $15? Should I even bother with Open Tee 1/2 since World Invitational is out?
Thanks for your time.

Hot Shots Shorties is separated into four game files, even if you buy this bundle.
Hot Shots Tennis: Get A Grip is worth more than $15, at least to me.
I suck at the golf games, so I can't answer the last question.
I sure hope more JRPGs from the PS2 era are given HD Collection treatment.. missed so many of them due to insane prices
You'd probably have to drop a few hundred dollars to get all of the .hack games now.