If you mean to use each letter only once, then twenty:
dag
day
fad
fag
fay
fly
gad
gal
gay
lad
lag
lay
agly
flag
flay
glad
lady
yald
glady
gadfly
If you mean to use each letter any number of times, then 59:
aal
add
aff
aga
ala
all
dad
dag
day
fad
fag
fay
fly
gad
gag
gal
gay
lad
lag
lay
yay
agly
alfa
alga
ally
dada
daff
dyad
fall
flag
flay
gaff
gaga
gala
gall
glad
lady
lall
yaff
yald
algal
allay
allyl
daddy
daffy
dally
faddy
gally
gayal
gayly
glady
dayfly
fallal
flaggy
gadfly
gladly
alfalfa
gallfly
lallygag
Some include:SadFadLad
18
dawn
You can make over 27 words with g f e d c b a g e d c b a g f e d c b a g f e
feed, fed, fade, deaf
You can make the word defers using all of the letters.Other words that you can make using some of the letters are:DeersDeferFeedsFreedFreesReedsReefsRefedSederDreeFreeSeedSeer
Some words that can be made with those letters are I, a, id, die, and fad. Some longer examples are dime and fazed.
Here are the words you can make from the letters RSFPJADGOC:adadoadosadsagagoapodapodsararcarcoarcsarfarfsarsasaspcadcadscapcapocaposcapscarcardcardscargocargoscarpcarpscarscodcodacodascodscogcogscopcopracoprascopscorcordcordscorfcorpscorscoscragcragscrapcrapscropcropsdadagdagodagosdagsdapdapsdodocdocsdogdogsdopadopasdordorpdorpsdorsdorsadosdragdragsdropdropsfafadfadofadosfadsfagfagsfarfardfardsfarofarosfasfjordfjordsfogfogsfopfopsforforafordfordsfragfragsfrapfrapsfrofrogfrogsgadgadsgapgapsgargarsgasgaspgogoagoadgoadsgoasgodgodsgorgorpgorpsgosgradgradsgraspjagjagsjarjarsjojogjogsoafoafsoaroarsocaocasododsofopopsororaoradorcorcaorcasorcsorsososarpapacpacspadpadspagodpagodsparpardpardspargopargosparspaspodpodspraopraosproproaproasprodprodsprofprofsprogprogsprosradradsragragsrajraprapsrasrasproadroadsrocrocsrodrodssacsadsagsagosapsaporsardsarodscadscagscarscarfscarpscopscragscrapscrodsosoapsoarsodsodasofasofarsojasopsorasordspaspadosparsprag
F R I D A Yair, aid, airydiary, day, dryfar, fair, fairy, fray, fryif,rid, raid, ray,yard
toe, do, foe, dye, dot,
adriftbuffeddefenddeferdefiledraftduffelfadfadefailedfedfeedfeudfiddlefiledfilledfiredfledfloodflowedfoodfoldforwardfreedfriedfueledfundfumedfusedoffedofferedpuffed
dogfish god gods dogs his fig gid dish go fog is dog fish