Current release of Uniprot, for idmapping_selected.tab and idmapping.dat for Human, Mouse and Rat: ftp://ftp.uniprot.org/pub/databases/uniprot/current_release/knowledgebase/idmapping/by_organism
All previous release of uniprot can be found here: ftp://ftp.uniprot.org/pub/databases/uniprot/previous_releases/
nextprot_ac_list_all.txt (Nextprot released on 13/02/2019 - current): ftp://ftp.nextprot.org/pub/current_release/ac_lists/
All previous release of nextprot_ac_list_all.txt can be foud here: ftp://ftp.nextprot.org/pub/previous_releases/