Are there good forums or sites or events that work well for pitching online using Zoom or whatever? What is your experience been?
There are forums but the term "good" is relative. Most entrepreneurs are nowhere near ready to pitch when they pitch. Practicing a pitch is futile if you haven't done the groundwork that will lead others to be interested in your pitch. Pitch forums are a lot like playing the lottery, mostly luck, no skill.
Instead of seeking pitch opportunities, an entrepreneur's time is best spent looking for ways to reduce risk, and how to birth their business without outside funds. Investors are interested most when you don't need their money. Consider how you would launch your business differently if you knew in advance that like 90% of entrepreneurs you would never receive a dime outside of friends or family. How would you trim your idea to something you could accomplish self-funded, that would lead to growing a nest egg allowing you to expand eventually into the ideal business you envisioned?
Investors don't pay for experiments. They look for things their money can amplify, not create. They're better for leaps like expanding manufacturing capacity, or accelerating growth in a market that has shown promising patterns through your proven efforts.
The more you reduce risks, including not being dependent on outside funds, the more appealing your eventual pitch will look to investors. Rather than shopping your idea around today, my recommendation is to use this isolation time to work on validating your marketing strategy and reducing every possible risk so you don't even need investors.