Hover flies

Hover flies hover over flowers before landing. They generally look like bees and wasps, but they’re flies.
Tufts Pollinator Initiative has a chart of common hover flies of New England, most of which would be common here in CNY as well.
Tachnid fly

These sometimes parasitize monarch pupas.
Sarcophaga flesh-eating fly

Horrible-sounding name!
Green bottle fly

Beautiful iridescent green.
Tiger bee fly (Xenox tigrinus)

An intriguing-looking insect that was resting awhile on our backyard chairs.