As you can see there are plenty of red and red-leaning cards if you feel like one combat per turn is just not enough
Promos (P) Promotional cards - like the aforementioned Lightning Bolt from MagicFest - can come from events, prereleases, special products, store promos, conventions, Secret Lair drops, and various other places where Wizards know we players are willing to pay top dollar for them
If theres a specific card that you want to add to your deck, you can usually buy it from online markets or gaming stores
But given the nature of the card, dead late, terrifying early, it's a no-brainer that 3 would still be the preferred number if legal
I purchased a few years ago from the 2002 Bakaboom one the 67/67 was denied which was kind of heartbreaking but I have a few more in que so maybe they grade the others