The NCBI BLAST family of programs includes:

BLASTP
Compares an amino acid query sequence against a protein sequence database

BLASTN
Compares a nucleotide query sequence against a nucleotide sequence database

BLASTX
Compares a nucleotide query sequence translated in all reading frames against a protein sequence database

TBLASTN
Compares a protein query sequence against a nucleotide sequence database dynamically translated in all reading frames

TBLASTX
Compares the six-frame translations of a nucleotide query sequence against the six-frame translations of a nucleotide sequence database. Please note that tblastx program cannot be used with the nr database on the BLAST Web page

Not Available on HOMD:

MegaBLAST
Compares a query to closely related sequences and works best if the target percent identity is 95% or more but is very fast

Discontiguous MegaBLAST
Uses an initial seed that ignores some bases (allowing mismatches) and is intended for cross-species comparisons

PSI-BLAST
Allows the user to build a PSSM (position-specific scoring matrix) using the results of the first BlastP run

PHI-BLAST
Performs the search but limits alignments to those that match a pattern in the query

DELTA-BLAST
Constructs a PSSM using the results of a Conserved Domain Database search and searches a sequence database