MTG Salvation

Hi all,
my son wants to build a decently workable Nicol Bolas themed legacy deck - but not a commander deck; a regular 60 card deck under legacy rules with as nicol bolas as the central theme. I'm not sure what to suggest, so I would really appreciate some ideas what would you guys recommend?
Many thanks in advance!

Many thanks!
How would you compare War of the Spark vs Throne of Eldraine in playability? ...I don't care particularly about "competitive format" - ie what is tournament legal for which standard and what will rotate out when, just casual play.
Thanks!

We recently started playing magic with our kids... bought the MTG Game night set and a few Throne of Eldraine boosters. Loving it. We bought the Commander Anthology II set for some more serious commander playing and thinking about buying also the Commander Anthology I set.

The kids want to learn more about deck-building and we're thinking of buying a couple of booster boxes and running some fun kitchen-counter "draft" evenings to learn how to draft, construct a basic deck and play.

HOWEVER, I'd like to buy 2 booster boxes from different sets for some variety in the cards and I would ideally like them eventually to be as useful as possible in future gameplay - i.e. to strengthen some of the commander decks and have more variety.
What booster boxes would you recommend I should go with as priority 1 and 2?

Many thanks!!!