Well, 1st off just know that DBZ, like most animes and video games, has been done many times before (although DBZ especially it seems like I've seen at least 40 different sets) so you're not gonna get many points for creativity.
Goku the Legend is overpowered. If it were 7/8 stars with the same stats it would be balanced. Not being destroyed by battle and getting a free draw engine is very big stuff. Additionally, similar cards that are not destroyed by battle and can be summoned without tribute have much much lower stats.
The Last Stand is heavily situational for a very weak effect, even if it is a quick-play card. Definitely underpowered. At least make it blow up all of your opponent's cards.
For Goku Battlefield, note that Field Spells are meant to be used by both players. If you wanted something only for your own monsters it should be a Continuous Spell card, not a Field Spell.
Refreshing Powers is in heavy need of rewording. Is the extra 400 ATK for 500 LP mandatory of optional? Is this a permanent ATK increase or is only until the end phase? Additionally, because this card can only be used in response to an attack, it should definitely be a Trap card.
Goku Ultimate Rage looks balanced.
Creativity: 6.5/10 (I give max 7/10 for cards based off anime or games)
Spelling/Grammar/Syntax: 1/10 (I counted, being lenient, 16 errors in spelling, grammar, or proper yugioh card syntax in your 5 cards. Not being lenient, the number is over 25 errors)
Pics: 7/10 (mostly good, some are so-so)
Card Balance: 6/10 (needs some work on some cards)
My Opinion: 5.5/10 (i've seen better DBZ cards on many occassions)
Final Rating: 5.2/10