Thermostable viral and microbial polymerases exhibiting a combination of activities selected from proofreading (3′-5′) exonuclease activity, nick translating (5′-3′) nuclease activity, synthetic primer-initiated polymerase activity, nick-initiated polymerase activity, reverse transcriptase activity, strand displacement activity, terminal transferase activity, primase activity, and/or efficient incorporation of chain terminating analogs. Some of the polymerases provided herein include a first motif and a second motif. The first motif preferably has the sequence X1X2X3DX4PX5IELRX6X7X8, wherein X1 is I or V; X4 is F or Y; X8 is G or A; and X2, X3, X5, X6, and X7 are any amino acid. The second motif preferably has the sequence RX9X10X11KSANX12GX13X14YG, wherein X11 is G or A; X12 is F, L, or Y; X13 is L or V; X14 is I or L; and X9 and X10 are any amino acid. Also provided are reagents for expressing the polymerases, polynucleotides encoding the polymerases, host cells expressing the polymerases, and methods of using the polymerases.