... the only way to get the lower to mid-elites is from the auction house. It's likely these cards will be needed for Team Diamond sets... so you may want to snipe them while the prices are reasonable. I think I've got all of them in my binder but it was always cheaper to build them from the lower sets unless lucky snipes were available.
For example there are 33 x 85 OVR Ultimate Kickoff cards (one for each team but for some reasons Saints have two). You could build them from 3 x 83 OVR Ultimate Kickoff cards which were selling for 15 - 20k ish. Now you have to buy the 85s off the AH... currently running about 50-60k each... but if they are needed for TD sets they'll be going for 90-120k like last year.
Note: the above are old gen xbox prices... which are probably different from ps4 or current gen auction houses... but the concept remains the same.