import re
p = re.compile(r'@([^\s:]+)')
test_str = "@galaxy5univ I like you\nRT @BestOfGalaxies: Let's sit under the stars ...\n@jonghyun__bot .........((thanks)\nRT @yosizo: thanks.ddddd <https://y...content-available-to-author-only...o.com>\nRT @LDH_3_yui: #fam, ccccc https://m...content-available-to-author-only...s.com"
print(p.findall(test_str))
p2 = re.compile(r'(?:http|ftp|https)://(?:[\w_-]+(?:(?:\.[\w_-]+)+))(?:[\w.,@?^=%&:/~+#-]*[\w@?^=%&/~+#-])?')
print(p2.findall(test_str))

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