There isn't much that's specifically 1/72, but there are
loads of 15,18, 25 and 28mm figures that work well in 1/72.
The (nominally 15mm but more like 20mm)
Battle Valor orcs ("Orcians") are
perfect Uruk-hai in 1/72. They're a bit shorter than humans, but "squat and broad" as per Tolkien (and with the requisite big heads, bow legs and long arms too!). The range also has warg riders and trolls/ogres. NB: the "Orcians" aren't representative of Battle Valor's range, size-wise: some of the other armies are much more traditional 15mm; their orcs are meant to be very big in that scale. I think the lizardmen ("Scalians") are similarly large.
The 18-20mm Blood Dawn orcs that Magister Militum used to do are about the same size as the Battle Valor ones but have a slightly more cartoony look. I think they may have just gone out of production, but the range may well have been sold by MM. They're also frequently available second hand.
For trolls and ogres, you're really spoilt for choice with 15-28mm manufacturers. It just depends how big you want them. Tolkien's trolls seem to have been 12'+ ("[There] came forward out of the trees three strange shapes. As tall as trolls they were, twelve feet or more in height...."), so if you want that sort of size, you're looking for trolls that are perhaps 40-50mm tall. Lots and lots of manufacturers make those. I'd have a look at the Ral Partha Europe range of
ogres and
trolls by Bob Olley.

You might want to take a look at the
goblins in the same range. While they're nominally 28mm, they're very small and delicate by modern standards. I have the AD&D group of five that Bob Olley did for Ral Partha; I think the RPE ones are an extension of that range. They are a bit bigger than the Battle Valor ones, but perfectly compatible with them as either elites or champions/leaders.
To give you an idea of scale, the integral bases are perhaps 16-18mm across (I don't have an unbiased one to measure, but there's a bit of room all round when they're based on 20mm UK pennies):

There are also wolf riders, with slightly idiosyncratic wargs in the Olley style. But there are also some old Tom Meier "lesser goblin imp" wolf riders that are exquisite and absolutely perfect for 1/72. They're at the bottom of the range (there are archers too):

A lot of the old Tom Meier Ral Partha goblins/lesser orcs would work well in 1/72 as well. They're still in production in the US, though they're expensive, but they frequently pop up on eBay; they've been produced more or less continuously since the late 1970s, so there are lots in circulation!
Other sources of orcs would be the old
Rieder Design goblin terrorists, now produced by Alternative Armies. They're quite nice miniatures that have aged well - I think the AA photo is a bit unflattering.
Alternative Armies also produce some of the
Rieder orcs, plus
some that have been converted more recently. I'm not 100% on the size of these, but I have a couple of the Rieder orcs from a different pack not yet back in production, and they'd work well in 1/72 if you don't mind your orcs on the large size. There are wolf riders too.
If you want Kev Adams goblins, AA do a group of
28mm lesser goblins by him that would work well in 1/72.
Denizen do
seven "true 25mm" orcs/goblins, all of which are very nice figures that are great for 1/72 (FA5, 6, 16, 18, 27, 39 and 45). They're roughly the same size as the Ral Partha ones - slightly more delicate, though.
There's
another Denizen range of goblins by a different sculptor. They're a bit more cartoony, and I couldn't swear to the size, but I suspect they're small enough to work in 1/72.
One more thing: the Nolzur's/Wizzkids/official D&D plastic figures are often compatible with 1/72. They're 28mm, notionally, but their proportions are much more in line with scale models (like 1/72) than traditional 28mm. The goblins are very small and fit with 1/72 ranges; the orcs are perfect as 1/72 ogres. I was playing 1/72 Hordes of the Things last night; my flyers are Nolzur's gargoyles, which look the part among Dark Alliance and Caesar orcs.
Hope that's some help!