Your search for "Letters with seals" returned 64 letters.
the seal is now gone but the copy of this letter by Canon Jackson includes a drawing of the original seal (which he labels '3 shallets')
papered seal, embossed with the Cavendish arms featuring three bucks heads cabossed
the seal is now gone but the copy of this letter by Canon Jackson includes a drawing of the original seal (which he labels 'Seal of Hardwick'; i.e. Embossed with Bess's arms featuring the Hardwick cross, a saltire engrailed, in chief three eglantines, surmounted by a countess's coronet)
papered seal, embossed
papered seal, embossed
papered seal, embossed
papered seal, embossed
papered seal, embossed
papered seal, embossed
papered seal, embossed featuring a heart and cross
papered seal, embossed featuring a heart and cross
papered seal, embossed with a Talbot dog passant (for the earls of Shrewsbury, a play on the family name Talbot), surrounded by the motto of the Order of the Garter 'Honi soit qui mal y pense' ('Shame be to him who thinks evil of this')
seal, red wax, embossed
papered seal, embossed
papered seal, embossed
seal over floss, red wax, embossed with the Lennox Stuart arms
papered seal, embossed with the Talbot dog passant (for the earls of Shrewsbury, a play on the family name Talbot)
papered seal, embossed with a Talbot dog passant (for the earls of Shrewsbury, a play on the family name Talbot) surrounded by the motto of the Order of the Garter 'Honi soit qui mal y pense' ('Shame be to him who thinks evil of this')
papered seal, embossed
papered seal, embossed