Your search for "Letters with seals" returned 64 letters.
seal, red wax, embossed featuring the Stafford knot
papered seal, embossed with Bess's arms featuring the Hardwick cross (a saltire engrailed, in chief three eglantines, surmounted by a countess's coronet)
seal, red wax, embossed with Bess's arms featuring the Hardwick cross (a saltire engrailed, in chief three eglantines, surmounted by a countess's coronet)
seal, red wax, embossed with Bess's arms featuring the Hardwick cross (a saltire engrailed, in chief three eglantines, surmounted by a countess's coronet)
seal, red wax, embossed with Bess's arms featuring the Hardwick cross (a saltire engrailed, in chief three eglantines, surmounted by a countess's coronet)
seal, red wax, embossed with Bess's arms featuring the Hardwick cross (a saltire engrailed, in chief three eglantines, surmounted by a countess's coronet)
seal, red wax, embossed with Bess's arms featuring the Hardwick cross (a saltire engrailed, in chief three eglantines, surmounted by a countess's coronet)
seal, red wax, embossed with Bess's arms featuring the Hardwick cross (a saltire engrailed, in chief three eglantines, surmounted by a countess's coronet)
papered seal, arms embossed
seal, red wax, embossed
papered seal, embossed
seal, red wax, embossed with the Cavendish stag trippant
seal, red wax, embossed with the Cavendish arms featuring three bucks heads cabossed
seal, red wax, embossed with the Cavendish arms featuring three bucks heads cabossed
two seals over ribbon (as can be seen from the image in the Sotheby's sale catalogue for 26 June 1974, lot 2840; the letter was sold into private ownership and its current location is unknown)
seal, red wax, embossed
seal, red wax, embossed
seal, red wax, embossed with the arms of the earls of Rutland
seal, red wax, embossed
two seals over ribbon, red wax, arms embossed