John Gill Commentary Deuteronomy 29:3

"the great trials which thine eyes saw, the signs, and those great wonders:" — Deuteronomy 29:3 (ASV)

The great temptations which your eyes have seen
Or trials, the ten plagues which tried the Egyptians, whether they would let Israel go; and tried the Israelites, whether they would believe in the Lord, and trust in his almighty power to deliver them:

the signs and those great miracles :
as the said plagues were such as were beyond the power of nature to produce, and which only Omnipotence could really effect.