valuable _adjectives

1-) worth a lot of money

VERBS

be, look
become
remain

ADVERBS

extremely, really, very
quite, rather
commercially

2-) very useful

VERBS

be, prove, seem
become
remain
make sb/sth
consider sth

ADVERBS

eminently, enormously, especially, exceedingly, exceptionally, extremely, highly, immensely, most, particularly, really, truly, very 
increasingly
quite
equally
inherently, intrinsically
potentially
ecologically, educationally, scientifically, socially

PREPOSITIONS

as
for
to