There are 18 8-letter words that start with 'sig'.
| siganids | sighless | sighlike | sighters | 
| sighting | sightsaw | sightsee | sigmoids | 
| signages | signaled | signaler | signally | 
| signeted | signiori | signiors | signiory | 
| signoras | signpost | ||
Note: These 18 8-letter words that start with 'sig' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with sign, sigh, sigm, sigl, siga, sigi.
4-letter words start with 'sig' (2)