Is there a way to see all of the different values in each field?

Try Vector => Analysis Tools => List unique values

Maybe another way:

1. press Open Field Calculator button in the "Attributes Toolbar" to open the Field Calculator;

2. find and select your Land Type column under Fields and Values node in the tree under Search textbox, then press All Unique button on the right.

To generate a comma separated list of all categories, you can use this expression:

concatenate_unique ( "landuse", concatenator:= ', ' )

You might want to add a condition like if ( "id" = 1, [expression], '') (substitute [expression] with the expreesion from above) to create the list only in one row and not in all of them to avoid excessive calculation of repeating values.