I will be formally adding a mention and the link to these in the rules I'm still composing, but wanted to post it here, in advance, since I've been receiving some questions about the need to own the actual OSE products.
The short answer is: No.
However, I discovered that a vast amount of OSE products were previously made available by another DM (who's no longer active on the forums) in an archived game:
These files, made available as read-only (meaning, you shouldn't be able to modify, make copies of, download, etc...) and allegedly with the publisher's permission, can be found
here and will cover
everything you would possibly need for this game.
If you're electing to use the Classic Fantasy character generation method, everything you could need will be included in the
OSE SRD, which is great, and which I will link to frequently.
If you're using the Advanced Fantasy character generation method, the extra class details are not included in the OSE SRD, and won't be included in a future SRD as it was released under a different license... which makes me suspect some of the files shared may not be exactly above-board, or shared with permission. I will, however, take that user at their word and point out what they have already shared. If, at any point, that user stops sharing, however, all access will be lost. But, for now, they could be useful for those that aren't invested in the official OSE products.