Words formed from any letters in riches plus optional blank

d -

sired₆

e -

siree₅

k -

siker₉

skier₉

l -

slice₉

slier₆

n -

since₉

siren₆

p -

speir₈

spice₁₁

spier₈

spire₈

s -

sices₈

sires₅

t -

stich₁₀

their₇

tiers₅

tires₅

trice₈

tries₅

u -

sieur₆

sucre₉

ureic₉

usher₈

v -

siver₉

vices₁₂

viers₉

vires₉

w -

weirs₈

whirs₁₀

wires₈

wiser₈

wries₈

x -

xeric₁₅

y -

yechs₁₂

z -

sizer₁₄