SnpEff is "the genetic variant annotation and functional effect prediction toolbox. It annotates and predicts the effects of genetic variants on genes and proteins (such as amino acid changes)."
SnpSift "[filters] large genomic datasets in order to find the most significant variants".
James K Bonfield, John Marshall, Petr Danecek, Heng Li, Valeriu Ohan, Andrew Whitwham, Thomas Keane, Robert M Davies. HTSlib: C library for reading/writing high-throughput sequencing data. GigaScience, Volume 10, Issue 2, February 2021, giab007, https://doi.org/10.1093/gigascience/giab007