The motto of Royal Highland Fusiliers is 'Nemo Me Impune Lacessit'.
Black Watch - Royal Highland Regiment -'s motto is 'Nemo me impune lacessit'.
Essex Regiment's motto is 'Montis insignia calpe'.
Aerial Rocket Artillery's motto is 'Duty not Reward'.
Contrary to a previous answer, this motto is nothing to do with the 17th/21st Lancers. The motto of the 17th/21st Lancers is 'Death or Glory'. 'Death before Dishonour' is the motto of 41st Battalion, Royal New South Wales Regiment, of the Australian Army. It's also the motto of 90 Armoured Regiment, of the Indian Army.
Royal Green Jackets's motto is 'Swift and Bold'.
Royal Norfolk Regiment's motto is 'Firm'.
The motto of Royal Malay Regiment is 'Ta'at Setia'.
The motto of Royal Australian Regiment is 'Duty First'.
Royal Hong Kong Regiment's motto is 'Nulli Secundus in Oriente'.
The motto of Royal Western Australia Regiment is 'Vigilant'.
King's Regiment's motto is 'Nec Aspera Terrent'.
Royal Ranger Regiment's motto is 'Agi Idup Agi Ngelaban'.
Royal South Australia Regiment's motto is 'Pro Patria'.
The motto of Royal Pacific Islands Regiment is 'To Find a Path'.
The motto of Royal Tasmania Regiment is 'Pro Aris Et Focis'.
The Royal New Brunswick Regiment's motto is 'Spem-Reduxit'.
Royal New Zealand Infantry Regiment's motto is 'Onward'.