I'm trying to KO several genes with CRISPR and I would like to have one donor plasmid for HR with a resistance gene and insertion sites for the homologous recombination arms.
I have used the pPNT6 plasmid a couple of times for that purpose. It contains a floxed Neo resistance cassette flanked by two multicloning sites. It also has a suicidal TK cassette outside the recombination cassette, that allows you to do negative selection of randomly integrated copies. It is available in Addgene (#11072). Hope this helps!