1. Buy a blade welder, and weld your own.
2. Learn to silver solder, and solder your own.
3. Buy pre-made, which is likely available for any machine as common as Delta
4. Have them made, any length/combo you want.
Options 1 and 2 are really only practical if you're using enough of the same blade stock to buy and stock spools. I've never been in that situation, as I tend to always want just 2 loops of each tooth configuration and blade width. Option 3 is going to limit your choices to what you can find / what Delta markets, but with a brand like Delta, maybe there's good options out there.
I've always used option 4. You can find several suppliers online who will weld a blade to your preferred length, so you can choose from the tooth shape, TPI, and widths they have in stock. I bought a crap ton of bandsaw loops over the course of about 10 years (2002 - 2012), and haven't needed to replenish since then, so I don't know all the suppliers out there today. I'd have to pull old receipts, but I think most of mine came from Southern Tool, and they seem to do a good job with both alignment and annealing, as I've never had a weld break and even the 1.5" wide blades track true.
For wood, ideal cutting is when you have 3 teeth in the kerf, and you'll probably want hook tooth config if you're cutting real thick stuff (eg. re-sawing over 6"). For thinner stuff, use higher TPI and not as much hook is needed. Wider blades run straighter, easier to make straight rips, but do require a lot more horsepower to spin (due to flex resistance).
Since pretty much every store-bought bandsaw on earth is grossly underpowered, I'd use this chance of swapping the motor to jump up to a real motor, at LEAST 1.5 horsepower, so you won't be frustrated doing thick cuts or running the widest blades that frame can carry. The only question I'd have there is how they're handling motor protection. I'd guess most small saws like that have the motor protection built into the motor, as having a dual-voltage motor would mean you'd have to manually re-arrange heaters in any external motor starter / protection circuit. Is there a red "reset" button on your motor?
Oh, one last thing. The reason most who weld or solder their own argue for those methods is that you can make cuts not possible with pre-welded blades, such as passing a blade thru a hole in your work without an entry cut. In other words, drill hole, thread blade thru it, weld, cut. I've got a lot of hours on bandsaws, and I've come across very few situations where this would be useful, or worth the time to do it. That's why they make scroll saws, anyway.