Woodelf Magic looks great. Pass without Trace is one of the better utility spells, lasts a good while, affects large groups, and is a big flat bonus. You might not always need stealth or the ability to hide, but this means that you and your entire party are all of a sudden very good at it, regardless of stats, skills or classes. A free druid cantrip is also good, because there's quite a few nice ones these days. Just a very nice feat overall for what it gives, even with Longstrider being a "meh" spell (except for stupid druid tricks, who have it already). You'll usually only need PwT once per day for non-combat use anyway, and this gives you exactly that, with a free cantrip to boot.
Human Determination seems nice too. Plenty to do with it in lots of builds. Sure, it's only 1/rest, but it's essentially a free actionless non-concentration spell on standby for anything you could possibly need to do, and do right the first time. Great feat. Lucky might be better in some ways (disadvantage into "super advantage", declaring use after the roll and not before it), but this does give you "proper" advantage (not just another die to roll, so it works with Sneak Attacks, etc), and having more advantage on-call is rather tasty no matter what you do with your character.
Flames of Plegithos + UA Lore Master arcane tradition is nice. All the fire, all the time, reroll ones. Of course, mixing that much UA at once may lead to unexpected rocks from ceilings. YMMV.
Gnome's Fade Away is probably abusable somehow, making it better than it seems (it's already rather good). Contested skill checks not breaking your invis, etc. I'll think of something useful and check that it's actually legit. There's also the difference between taking an attack "action", and actually attacking something (there were a few options in last week's skill feats UA, but none are applicable here).
((I know block and tackle doesn't actually work like this, but a lvl8 moon druid could wildshape into a giant eagle and use himself as the attachment point of a rock gnome's Lifter. With the Brawny feat from last week, you're looking at a 5700 pound lift capacity (about 2 1/2 tonnes). So not quit a heavy airlift chinook, but not bad either. Because, screw physics or logic, this is DnD))
