The last few rounds will naturally seem weaker when you've been mainly looking at guys taken on days 1 and 2. There are a still a lot of players with great upside they just have very low floors as well.
Here are a few late round/UDFA guys that seem Seahawky to me for various reasons (physicals, SPARQ, backstory):
QB: Cole McDonald, Steven Montez
RB: La'Mical Perine, Christian Gibson
TE: Stephen Sullivan, Charlie Woerner
WR: Darnell Mooney, Malcolm Perry, Devin Duvernay, Ben Victor, Dezmon Patmon, Josh Pearson
OL: Alex Taylor, Justin Herron, Hakeem Adenjii, Charlie Heck, Kevin Dotson, Austin Capps, Cordel Iwuagwu
DT: Benito Jones, Darrion Daniels, Larrell Murchison, Malcolm Roach, DaVon Hamilton, McTelvin Agin
LEO: Casey Toohill, DJ Wonnum, Alex Highsmith, Azur Kamara, Jon Garvin
DE: Nick Coe, Rob Windsor, Jonah Williams
LB: Khaleke Hudson, Cameron Brown, Cale Garrett, Evan Weaver
CB: Michael Ojemduia, Bryce Hall, Ray Buford, Kindle Vildor, BoPete Keyes, Reggie Robinson, Delrick Abrams (33 1/4" arms)
S: JR Reed, K'Von Wallace, Daniel Thomas, Josh Metellus, Alohi Gilman, Luther Kirk