The Denver Zoo displays giraffe as one exhibit on their hoofstock loop, not as part of a mixed exhibit.
Sacramento currently keeps theirs solo, but this will be changing if the new zoo comes to fruition. The only other facilty I've seen them solo is Six Flags Discovery Kingdom. Mixed species exhibits include Woodland Park, Oregon, Wildlife Safari, San Francisco, Fresno Chaffee (both their old exhibit and current), San Diego, and SDZSP.
I feel like objectively, having giraffes on their own isn't economical in zoos. They take up a lot of space and they're usually really placid to other herbivores so it's a no-brainer to have other hoofstock in there.
Ueno Zoo keeps them alone and Tama used to feature a mixed-species exhibit with the giraffes but they are alone now.
The only Brazilian zoos which hold giraffes in mixed exhibits are Cotia (not open yet), Pomerode (two cows live with an ostrich) and Brasília (a cow lives with waterbuck). Mangaratiba, São Paulo (Zoo Safari included), Penha (Beto Carrero World) all have them by themselves. I guess this was the trend before zoogeographical exhibits almost became the norm in the developed world.
The zoos I visited: Mixed-species exhibit: - Hagenbeck - Zoo Berlin - Tierpark Berlin (planned) - Jaderpark - Erlebniszoo Hannover - Safariland Stukenbrock - Zoo Osnabrück - Zoom Erlebniswelt - Zoo Köln - Zoo Nürnberg - Stuttgart (Wilhelma) - Serengetipark Hodenhagen - Chiang Mai Zoo - Dusit Zoo (closed) - Zoo Melbourne - Australia Zoo - Burgers Zoo - Dierenpark Emmen (closed) - Wildlands Emmen - Artis Amsterdam - Zoo Zürich - Pairi Daiza - Yorkshire Wildlife Park Just Giraffes: - Zoopark Erfurt (until 2021) - Allwetterzoo Münster - Duisburg (until 2023) / (mixed indoor exhibit with Ground Hornbills) - Zoo Dortmund - Zoo Frankfurt - Tierpark Hellabrunn - Zoo Magdeburg (with Zebras in the past?) - London Zoo (possibly with Zebras?)
- The fifteen giraffes in Mangaratiba are owned by Rio and they plan to bring at least two or three of them to live with some medium-sized herbivores and African birds. Before this, they used to have their giraffes by themselves or with zebras and ostriches. - I forgot about Itatiba, which also displays giraffes by themselves. There are three pens: one for Ayana, their Southern giraffe, and two more for their "Rothschild's" giraffes. They display them like this since their original pair of Northern giraffes arrived, in 2017. Before this, Ayana was their only giraffe and she was displayed with their late Abyssinian ground hornbill and some grey crowned cranes. - Americana held a Masai cow all by herself. - Belo Horizonte had theirs with waterbuck and zebras, but the last giraffe died in 2015. - Curitiba displayed their generic and Rothschild's giraffes with ostriches and peafowl. - Sapucaia do Sul had their Rothschild's all by themselves. - Salvador had giraffes, but I don't known if they were held by themselves, they died a very long time ago. - Goiânia had two reticulated bulls exhibited by themselves, but they died around 2009 or 2010.
Indonesian zoos generally didn't really mix giraffes. IIRC Taman Safari, Ragunan, and Batu Secret Zoo kept giraffes in their own exhibit.