What are some heat resistant flowers?

https://www.thisoldhouse.com/ideas/drought-resistant-annuals

Marigolds can take hot weather.....they can take about anything. They are good for around gardens also.

Portuilaca is so cheerful. Love the sun. Most succulents as well.

I would suggest you go to your local garden store or google your area for ideas. They would have great ideas. Here is a start - https://www.southernliving.com/home-garden/gardens/bes-plants-for-containers#vogue-audrey-mandevilla

Lantana thinks hotter is better. A Miss Huff is perennial and there are several are annual, those would be better for pots. Miss Huff can get pretty big. I get tons of butterflies on mine. I just love them. Lots of herbs like it hot, as well, so mix some in with your flowers.

I have always had good luck with vinca flowers (not the vine). They come in an assortment of colors and will hold up in the heat of summer. They do well in sun as well as shade.

Sunflowers should be able to take the heat without any problem.

Mexican heather and vinca are very drought tolerant.

http://www.weekendgardener.net/garden-plants/high-heat-flowers-080908.htm

https://www.bhg.com/gardening/container/plans-ideas/container-garden-plants-that-take-the-heat/

http://balconygardenweb.com/best-flowers-for-full-sun-heat-tolerant-flowers-for-containers/