I teach high school at an independent school and we had several days worth of orientation just crowd sourcing all of the tools people have tried. Here are some of my favorites that you might check out:
If you have access to the Google Education Suite, Google Jamboards are a really neat way for students to collaborate on a virtual whiteboard. Bonus is that it integrates well with Google Classroom.
A web-based app called Hypothesis (https://web.hypothes.is/) is an interesting tool I'm using to have students annotate and engage with text collaboratively. It may not be as friendly to elementary students, but I'm not as familiar with that age group. I know some of our MS teachers are using it.
Padlet is a neat tool where students can post responses and then they can be sorted, color coded, etc. When in-person I do a lot of activities with sticky notes where students put down their questions and ideas and then we sort them, create timelines, models, etc. Padlet seems to be a good virtual tool for that. One of our 6th grade science teachers uses Padlet religiously (even when in person) to get students to post their "wonders".
Quizizz is one I haven't tried myself yet, but it was demonstrated for us by a colleague and it seems like it could be a really useful tool especially for formative assessments on content. There are lots of different modes you can use to create questions to make them more engaging and if you select that option, Quizizz will automatically add funny memes between questions.
EdPuzzle is a tool that allows you to embed questions into videos at strategic points. So if you assign a YouTube video for example, you could put questions that check for understanding at certain key points.
Finally, something I am really liking so far is digital interactive notebooks using Google Slides. There are lots of videos available with examples, you can find free templates and paid templates on Teachers Pay Teachers. So far I'm finding that they take a long time to create, but once you've created them, they make life a lot easier! If a student is absent or for some reason loses connection, you can just make sure they know which slides you're working off of that day. It seems to be sort of a virtual equivalent of a lab notebook that has students keep everything in one place.