Umbreon EX probably won't be as good in the current meta as it used to, since the main attack is specifically designed to be amazing versus Mega EX Pokémon, but the new sets are going to be printing GX Pokémon rendering that attack useless. Umbreon GX is good though.
There's a few prints of normal Yveltal, most of which are very playable. The break is good in certain decks also. Yveltal EX is good to if you have it, again in certain decks.
If you're looking to play competitive I would recommend looking into what tournaments around you play as far as standard or expanded. In my area just about everything is standard, and I prefer that anyway so that's pretty much all I play. Standard rotates every year in September (Or close to it, depending how the calendar falls). Expanded has never rotated since it's creation, but people are speculating with Sun and Moon it will have it's first rotation. Again, that's just speculation, nothing official will be announced till closer to the world Championships.
Current standard rotation is XY Primal Clash to the current set. (Sun and moon base set) Current expanded rotation is Black and White base set to current. The promo's also rotate, but I can never remember which number starts the current standard rotation so if you have promo's that are kinda old mention them and someone will know where they fall. Also, there are a couple of banned cards, but I think they only fall in the expanded area so if you play standard you don't need to worry about them.
Juniper/Sycamore are functionally identical, which is why there's actually a special rule that you can't have both in your decks ever. For causal play most people won't care if you mix the two as long as you don't put more than four in, but for tournament play you'll need to have one or the other.
Supporters that draw (In standard, there are more in expanded):
Professor Sycamore: Discard hand, draw 7
N: Both players shuffle hand to deck, draw based on number of prizes remaining
Professor Birch: Shuffle hand to deck, flip coin. Heads draw 7, tails draw 4
Shauna: Shuffle hand to deck, draw 5
Those are the ones typically played competitively, with the first two being FAR more popular than the last two.
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Below are others I thought of, but are typically considered less competitive or are niche and therefore at least are not going to be your main draw engines. Some might be a 1-of in a deck, others you'll never play once you have the "Good" ones listed above.
Tierno/Hau: Draw 3
Lass's Special: Draw a card for each opponent's benched Pokémon
Giovanni's Scheme: Choose 1: Attacks this turn do 20 extra damage, or draw until you have 5 cards in hand
Lillie: Draw until you have 6 in hand. If it's your first turn, until you have 8
Teammates: Only playable if your Pokémon was knocked out on the prior turn, search for two cards from your deck.
Ace Trainer: Only playable if you have more prizes than your opponent. Both players shuffle hand to deck. You draw 6, opponent draws 3
Professor Kukui: Draw 2, and attacks do 20 more damage this turn
I'm sure I forgot some. The last four do see play in specific decks, but the first three never do as far as I know. (Giovanni being outclassed by Kukui; it saw play a little before Kukui came out)
Hope this helps! If you have any more questions just ask. Also, these were just supporters I thought of. There are many item cards that let you search for specific cards, and some that let you draw.
