There is legal content, yes. But content makers who actually put their content under a free license and advertise it as free-as-in-freedom are rare. And the rest is either drowning inmidst content of at least questionable origin without being advertised as legal (much less licensed free-as-in-freedom) or hard to find.
First of all, of course, there are the old household names. Linda Kellie should be quite well-known, but her creations can mostly be found either on instances of her own OARs (e.g. Freebie Mall, Clutterfly; both are included in the EQG Mall, https://opensimworld.com/hop/83060
) or built into sims instead of directly offered as freebies. As for clothing, there was Taarna Welles with her product lines La Baronnie, ReMake and Reboot. Apart from her own sims Savvy (https://opensimworld.com/hop/75031
) and La Baronnie (not on OSW, but on the same grid as Savvy), very few sims offer her creations. Other names which, AFAIK, stand for legal content, but who have disappeared, are Hylee Bekkers and Selea Core whose works are somewhat easier to find but still kind of rare; besides, AFAIK, they've never put them under any license.
The only mesh bodies which are guaranteed to be legal are those with Ruth and Roth in their names or based on such, e.g. Sean Heavy's RuthToo and RothToo, Shin Ingen's Ruth 2.0 RC#3 and Roth 2.0 RC#1, Hyacinth Jewell's LuvMyBod and, most recently, Ai Austin's BoM-enabled Ruth2v4 and Roth2v2. I'm not sure about Sean's bodies, but AFAIK, the others are all under various free licenses. Austin's BoM bodies are so hard to find that even many freebie store owners don't know they exist, and most of those who do flat-out refuse to offer them because not only are these more natural bodies a far cry from the various demigod-like bodies based on copybotted material, but especially Roth2v2 (and to a lesser extent Ruth2v4) has a preview image that is so hideous that it makes people go absolutely ballistic with outright hatred. Also, the official RuthAndRoth sim on OSgrid isn't here on OSW, so if you're interested in these bodies, you'll have to do some detective work or search OSgrid for RuthAndRoth. Austin's bodies are all over the place, especially in older freebie sims, but technically outdated as of last year. LuvMyBod is exclusive to Hyacinth's sims.
Some more legal clothing comes from Otto von Otter whom I know personally. Now, for obvious reasons, I can only talk about gentlemen's clothes. If you're looking for legal material only, you have to be careful. He admits himself that some of what he offers in his own Klamotto store is outright copybotted. But his older clothes which tends to come in a lot of colour variations is legal (e.g. Gavin jackets, Ed shirts, Peak suits, Oscar coats, Broberry jeans, Dandy and Monk shoes). It does come from Second Life, but he worked together with content creators in SL, got shapes and textures from them and turned them into a whole lot more variations than the original creators offered. That was in the early days of mesh clothes in OpenSim when there weren't even absolute basics for men.
Also, these earlier Otto von Otter clothes are the only legal clothes that work reasonably well on Roth2 because there are exactly zero free clothes (and precious little Kitely-exclusive payware) available that were made for any Roth2 version. (Or if there are, they're pretty well-hidden.)
There are a few creators of clothing for Ruth2. You can find their works at Shinobar Annex (https://opensimworld.com/hop/82007
), Bella Klara (https://opensimworld.com/hop/81258,
and there's even more on that sim that Klarabella Karamell has made that's legal), BerniciaWorld (https://opensimworld.com/hop/82458
) and at the Covey Stores which now reside in the new mall sim on Fire and Ice Grid.
Furthermore, start at Outworldz Welcome (https://opensimworld.com/hop/74834
) and check out Ferd Frederix' creations. "Prolific" doesn't begin to describe him, not to mention that he's one of the Metaverse's most skilled scripters.
Finally, I'm pretty sure the radios from OSWRS (https://opensimworld.com/hop/82749
) are legal.
What makes things more difficult especially for newbies who haven't been around for long enough is the tendency of grid admins to always set their own identities as creators of everything they put on a sim, including the freebies they offer in their freebie malls. This makes it impossible to trace the origins of content by means of creator tag.
Some creators tag their content accordingly so you can see that it was them who created something by hovering your mouse over it. For example, if the name starts with "Hylee's", it's safe to assume it was made by Hylee Bekkers, therefore it's legal. It works similarly with Selea Core. In both cases, I recommend picking up the items at freebie stores instead of in the wilderness, for especially Selea Core had a distinct look for her boxes. As for Linda Kellie, I've seen her creations both renamed and recredited but otherwise vanilla, so you have to know what they look like in order to know that they're legal. And as for Otto von Otter, you have to know the story behind his clothes to know that the Gavin jackets and Peak suits that everyone and their dog puts in freebie stores are legal.
Last but not least: Anyone who reads this and knows more creators of legal content, feel free to post them here in this thread!