Here's the list of agents that are better than SARS:
https://en.wikipedia.org/wiki/Bioterrorism#Types_of_agents
Edit:
So far I'm dissapointed with the comments to my post. I can't tell if some of these are trolls or not, but generally they don't add much to the discussion.
These hypotheticals are specious, sure they sound like lucid idea but with even a slight amount of criticism they'd fall apart. I'm going to posit some ideas here. Why didn't China weaponize H5N1? It has a higher Ro and CFR. It is commonly found throughout Southeast Asia and is what most pandemic experts thought was going to be the next pandemic. How would a virus get through a biosafety level 4 lab? If anyone else here has experience in biosafety labs I'm all ears, but I'd be shocked that a virus would be able to escape from something like that; not that mistakes don't happen but this isn't exactly a durable pathogen. Then we have the issue of every single advanced military in the world wouldn't even touch The Coronavirus family. I'm going to go ahead and assume that the people who are making bioweapons are good at their jobs and can recognize what makes a good bioweapon and what doesn't. Finally, there are just so many better options for bioweapons. The US invests massive amounts in making precision weapons because when you're a military power hitting a precise location is what's key. COVID is like a cluster bomb that has 90% duds.
But after all of this, instead of random people on the internet, we have experts who have time and time again said that COVID is not a bioweapon:
https://www.washingtonpost.com/world/2020/01/29/experts-debu...
https://www.nature.com/articles/s41591-020-0820-9?fbclid=IwA...
https://www.livescience.com/coronavirus-not-human-made-in-la...
https://edition.cnn.com/2020/02/18/politics/coronavirus-cott...
https://www.ft.com/content/a6392ee6-4ec6-11ea-95a0-43d18ec71...