Here are ten sets of seven letters, each consisting of only 1-point tiles, that have only one anagram, which is a fairly everyday seven-letter word, and which also contain two Is (as a bonus, one has three Is).  What are those everyday words?

AAIINRT
AEIINRR
AIIILNT
AIILNOS
EIILLRS
EIILORS
EIILSTT
IILLNST
IILNORS
IINOTTU

And, here are five extra sets, not quite so easy, also containing only 1-point tiles that also have only one anagram and with two Is.  They are the sorts of combinations of letters that you may well find on your rack, since Is do have a habit of arriving in pairs.  What are these not quite so everyday words?

AEIILNN
AIILNTU
EEIINST
EIILNOT
IIOSTTU

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The ten “easy” words:
AAIINRT              ANTIAIR              directed against attacking aircraft
AEIINRR              RAINIER              RAINY, marked by rain
AIIILNT               INITIAL               at the beginning
AIILNOS               LIAISON               a means of maintaining communication (among other meanings)
EIILLRS                SILLIER                showing a lack of common sense
EIILORS               SOILIER               dirtier, more soiled
EIILSTT                ELITIST                an adherent of elitism
IILLNST               INSTILL               to infuse slowly, also INSTIL
IILNORS               SIRLOIN               a loin of beef, or the upper part of the loin
IINOTTU             TUITION             a fee for instruction [n -S]                         

And the five less easy words:
AEIILNN              ANILINE              a coal-tar product used in dyeing, also ANILIN
AIILNTU              NAUTILI              a spiral-shelled mollusc
EEIINST               SIENITE               a coarse-grained igneous rock, similar to granite
EIILNOT               ETIOLIN               a yellow pigment in light-starved plants
IIOSTTU               OUSTITI               a lock-opening tool