I have created a DPS calculator for Deadfire. I used a custom function (Makro) to calculate how the game handles stacking of multipliers (it is neither simply multiplicative nor additive). The row above the main table is to enter your character values (your accuracy, damage multipliers from talents, equipment bonuses,...), but the bonuses from your weapons are listed separately in the table. To calculate the total multiplier for one of your stats, you have to use my custom function WMULT (). Let's say you have a damage bonus of +15% from might, +20% from soul whip and -30% from another talent, then you have to enter "=WMULT(1.15;1.2;0.7)" into the "dmg mult" field above the table. If you have another +10% damage bonus on your weapon, you enter that into the table. I am not very far into the game, so i have only added the base weapons, but you should be able to add any other weapon to the table to calculate DPS.
Edit: Added dual-wield bonus, added modal abilities, added spell dps
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