While this information is in good dictionaries, I have sometimes wanted a more convenient list of words used in Epic which start with the digamma. So I have brought together information from several sources here. The starting point for my list is pp.45-47 of Seymour's Introduction to the Language and Verse of Homer, with additional details from Monro's Homeric Grammar and Benner's Selections from Homer's Iliad.
The most obvious effect of the digamma is hiatus, but it's capable of introducing more exotic effects into the hexameter line. The missing digamma may make position (that is, close a preceding short-vowel syllable and make it scan long), and finally it may even be treated like one of the resonants (λ, μ, ν, ρ and ς) and be doubled, causing a preceding short vowel to scan long (ἀποεἰπών scanned u---), a remarkable effect for a consonant that may well have disappeared from Homer's own speech.
Historical linguists will perhaps be made queasy by my list below, since I have mixed words which originally started with *w- and those with *sw-. Nor have I included words starting with ῥ- since that almost always lengthens a preceding short vowel, regardless of whether it reflects original *wr- or not. Since my concern here is metrical, and in Homer the metrical outcome of these is the same, I haven't made any effort to separate the words by etymology. For this information you should consult the usual historical linguistics references.
ἁλῶναι to be captured
ἄναξ king, and ἀνάσσω rule
ἕ οὗ οἷ (more often enclitic) 3rd.sg. pronoun him, etc.
ἔαρ spring, and εἰαρινός
ἕδνα wedding gifts
εἵματα see ἕννυμι
εἶπον 2.aor. say
εἴρω, ἐρέω say
ἑκάς far, and the many compounds, e.g. ἑκηβόλος, κτλ.
ἑκών willing, and ἕκητι, ἕκηλος
ἕλιξ twisting, winding, and ἑλίσσω
ἐλπίς, ἔλπομαι expect
ἔοικα be like
ἑός ἑή ἑόν (also appearing as ὅς ἥ ὅν) 3rd.sg. possessive his, her, its
ἕννυμι, ἐσθής, εἵματα clothe, clothing
ἔρδω, ἔργον work
ἐρύω, ἔρρω pull, draw, go
ἐσθής see ἕννυμι
ἦθος accustomed haunts
ἰδεῖν 2.aor. see (but not indicative forms in εἶδ‐)
ἴκελος resembling, like
ἴς, ἶφι strength
ἴτυς rim, edge (of wheel or shield)
The main internal digammas to worry about are in the related words δήν and δηρόν. An open short vowel before either of these words may scan long, reflecting the consonant cluster dw-
In later elegiac and choral poets the digamma — an artificial borrowing from Epic for many of them — can account for cases of hiatus, but it was not used to make position.