If you want to buff this Commander Deck, other cards that make artifacts hexproof and/or indestructible could certainly be very fun, as barring a board wipe, this would prevent most damage, and help to keep your Commander alive, and annoying
You can also buy individual packs and cardboard-sleeved ones
Because it makes all cards Blue in all zones, it means Llawan will bounce all opposing creatures and then prevent your opponents from casting all of those creatures
It will only start drawing cards consistently when youre Blitzing it from your graveyard, but Tenacious Underdog turns into a clock that grants you an absurd amount of card advantage over time
This is especially true since you get counters when the opponent's permanents are put into the graveyard, but his ability exiles permanents, so you're busy finding other ways to fill the graveyard