I don't think any 2020 thread is complete without the AlphaFold paper (hype aside):

https://www.nature.com/articles/s41586-019-1923-7

Probably the scvelo paper should be mentioned. There are a large number of starts and issues at their Github, plus Bioconductor wrapped it into an R interface via the velociraptor package, I guess that qualifies as influential. I did not check how many citations of papers it had that actually used it for some biological inference though.

https://www.nature.com/articles/s41587-020-0591-3

Even though it is a controversial topic among many of my colleagues I liked this paper

Hou, W., Ji, Z., Ji, H., & Hicks, S. C. (2020). A systematic evaluation of single-cell RNA-sequencing imputation methods. Genome biology, 21(1), 1-30.

https://genomebiology.biomedcentral.com/articles/10.1186/s13059-020-02132-x

This issue is far from settled, but definitely a step in the right direction.

A complete domain-to-species taxonomy for Bacteria and Archaea

• https://www.nature.com/articles/s41587-020-0501-8