First, if you want to find the list of boundary conditions on a specific solver do this:
solverName -listVectorBCs
solverName -ListScalarBCs
To get info about a specific boundary condition use
foamInfo NameOfBC
The complete list of boundary condition types in OpenFOAM are listed here:
$FOAM_SRC/finiteVolume/fields/fvPatchFields/basic
Second, current boundary conditions for pressure are as follows. They can be used for inlet, outlet, wall or all:
1. fixedFluxPressure: This boundary condition sets the pressure gradient to the provided value such that the flux on the boundary is that specified by the velocity boundary condition (for wall and inlet)
2. totalPressure: This boundary condition provides a total pressure condition. Four variants are possible (for inlet and outlet).
3. fixedValue: This boundary condition supplies a fixed value constraint, and is the base class for a number of other boundary conditions (for all).
4. zeroGradient: This boundary condition applies a zero-gradient condition from the patch internal field onto the patch faces (for all).
5. pressureInletOutletVelocity: This velocity inlet/outlet boundary condition is applied to pressure boundaries where the pressure is specified. A zero-gradient condition is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the patch-face normal component of the internal-cell value (for inlet and outlet).
6. fanPressure: This boundary condition can be applied to assign either a pressure inlet or outlet total pressure condition for a fan (for inlet and outlet).
7. rotatingPressureInletOutletVelocity: This velocity inlet/outlet boundary condition is applied to patches in a rotating frame where the pressure is specified. A zero-gradient is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the flux with a direction normal to the patch faces.
8. rotatingTotalPressure: This boundary condition provides a total pressure condition for patches in a rotating frame (for inlet and outlet).
9. uniformTotalPressure: This boundary condition provides a time-varying form of the uniform total pressure boundary condition (for inlet and outlet).
10. fixedFluxExtrapolatedPressure: This boundary condition sets the pressure gradient to the provided value such that the flux on the boundary is that specified by the velocity boundary condition (for inlet and wall).
11. activePressureForceBaffleVelocity: This boundary condition is applied to the flow velocity, to simulate the opening or closure of a baffle due to area averaged pressure or force delta, between both sides of the baffle. This is achieved by merging the behaviours of wall and cyclic baffles (coupled?).
12. phaseHydrostaticPressure: This boundary condition provides a phase-based hydrostatic pressure condition (generic B.C).
13. prghPressure: This boundary condition provides static pressure condition for p_rgh (generic B.C).
14. prghTotalHydrostaticPressure: This boundary condition provides static pressure condition for p_rgh (generic B.C).
15. prghTotalPressure: This boundary condition provides static pressure condition for p_rgh (generic B.C).
16. uniformDensityHydrostaticPressure: This boundary condition provides a hydrostatic pressure condition (generic B.C).
17. fixedPressureCompressibleDensity: This boundary condition calculates a (liquid) compressible density as a function of pressure and fluid properties (for inlet).
18. freestreamPressure: This boundary condition provides a free-stream condition for pressure (for inlet and outlet).
19. plenumPressure: This boundary condition provides a plenum pressure inlet condition. This condition creates a zero-dimensional model of an enclosed volume of gas upstream of the inlet. The pressure that the boundary condition exerts on the inlet boundary is dependent on the thermodynamic state of the upstream volume. The upstream plenum density and temperature are time-stepped along with the rest of the simulation, and momentum is neglected. The plenum is supplied with a user specified mass flow and temperature (for inlet).
20. pressureDirectedInletOutletVelocity: This velocity inlet/outlet boundary condition is applied to pressure boundaries where the pressure is specified. A zero-gradient condition is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the flux with the specified inlet direction (for inlet and outlet).
21. pressureDirectedInletVelocity: This velocity inlet boundary condition is applied to patches where the pressure is specified. The inflow velocity is obtained from the flux with the specified inlet direction (for inlet).
22. pressureInletOutletParSlipVelocity: This velocity inlet/outlet boundary condition for pressure boundary where the pressure is specified. A zero-gradient is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the flux with the specified inlet direction (for inlet and outlet).
23. pressureInletUniformVelocity: This velocity inlet boundary condition is applied to patches where the pressure is specified. The uniform inflow velocity is obtained by averaging the flux over the patch, and then applying it in the direction normal to the patch faces (for inlet).
24. pressureNormalInletOutletVelocity: This velocity inlet/outlet boundary condition is applied to patches where the pressure is specified. A zero-gradient condition is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the flux with a direction normal to the patch faces (for inlet and outlet).
25. pressurePIDControlInletVelocity: This boundary condition tries to generate an inlet velocity that maintains a specified pressure drop between two face zones downstream. The zones should fully span a duct through which all the inlet flow passes (only for inlet).
26. syringePressure: This boundary condition provides a pressure condition, obtained from a zero-D model of the cylinder of a syringe (only for inlet).
27. waveSurfacePressure: This is a pressure boundary condition, whose value is calculated as the hydrostatic pressure based on a given displacement (only for inlet).
source: https://www.openfoam.com/documentation/user-guide/a-reference/a.4-standard-boundary-conditions