I have a monthly budget to spend on freelancers. What would you ask them to work on? Small projects or go all-in on one big project? Ideas?
Whatever your full time people either can’t do or would be so miserable doing that they’d quit if you put them on it for more than a few days at a time.
I would ask them to work on solutions for office tasks that should be automated or are otherwise annoying or barriers to faster/quality delivery. I would ask for documentation describing the problem to be solved before work begins and a review of their tested solution once it is functional.
Tedious development tasks.
I would have them do small pieces. Specifically I would have them write tests. Unit tests, regression test, etc.
This question will produce absolutely no valuable answers without providing at least a bit of context.
What are you trying to accomplish? What problems are you facing? What do you intend to do with this budget?
You can hire 100 code monkeys and have them accomplish _anything_ just to say you spent the budget, or you can provide rigid leadership in a certain direction. It's up to you to decide whether they succeed or fail.