Hey! Thanks for the question - and those are all really cute. I'll try to find some similar options for you. I might throw in a couple ones with some pretty, neutral gemstones (just in case you're interested.) For those shopping along at home - here are the three that Reader E likes (I think the love knot dangles are my favorite.)
Lauren by Ralph Lauren Braided Knot Earrings at Bloomingdales ($32 - an interesting take on the knot stud.)
Anne Klein Button Stud Earrings in blue at Nordstroms ($20 - I love this blue/gray color - it would be a lovely neutral in a wardrobe but still add some nice color around the face. These earrings also come in two shades of white and a turquoise...a really nice basic for anyone I think.)
Hammered Metal Square Studs at Forever 21 ($1.80 - yes...that price is right. Still have to pay shipping but there are TONS of earrings on final sales for $1.80 right now at F21.)
Tina Tang Small Disc Earrings at ShopGoldyn ($42 - these are pretty and a bit more rustic - I like them.)
Silver-Tone & Glass Pearl Earrings at Lord & Taylor ($24 - pretty and simple dangle earrings.)
Kate Spade Dot to Dot Stud Earrings at Bloomingdales ($48 - I know these are a bit different then what you wanted but they're so pretty I thought I'd point them out.)
Okay - thats a bunch of different options for you. Let me know which of them you like best and I can always find you more. :-) Happy shopping! I'm sure any of them will look lovely on you. Come see me when you want coordinating necklaces. ;-)