Narset is an easy inclusion in any blue control deck
Sure, some creatures are more useful than others, and you're limiting the number of times you can pull off various graveyard shenanigans, but if this isn't a major focus of your deck, who wouldn't like, say, a free Craterhoof Behemoth for a turn
Kill a creature and destroy a 'walker
Full Grip is an excellent site if youre mainly looking for Pokemon or Magic cards, with a huge selection and reasonable prices
While Play Boosters are likely to be reprinted regularly, Collector Booster packs are going for as much as $149.99 - for fifteen cards, where as booster displays are rocking up to $1400 right now as well
Dragons is a great choice if you like tuning decks, but you'll probably want to look elsewhere if you are looking for broad cards that can send you in a bunch of different directions