inb4, an aegisub script that adds content before a line. This has probably been done 200 billion times but whatever.

gistfile1.lua

-- Do whatever you want.

script_name = "inb4"
script_description = "Adds content before selected lines. Useful for OPs where you want \\fads or \\blurs, like every Commie OP ever."
script_author = "t4w"
script_version = "0.0.1a"

function inb4(subs, sel)
	local t = ipairs(sel)
	for __, i in ipairs(sel) do
		aegisub.progress.task("inb4ing line " .. string.format("%d", i+1))
		local line = subs[i]
		line.text = res.inb4 .. line.text
		subs[i] = line
	end
end

function dialog(subs, sel)
	gooey = {
		{ x = 0, y = 0, width = 10, height = 1, class = "edit", name = "inb4", value = "{\\fad(200,200)\\blur4}" },
	}
	buttons = { "Insert Before", "Cancel" }
	pressed, res = aegisub.dialog.display(gooey,buttons,{cancel='Cancel'})
	if pressed=="Insert Before" then 
		inb4(subs, sel)
	end
end

function main(subs, sel) 
	dialog(subs, sel)
	aegisub.set_undo_point(script_name)
	return sel
end

aegisub.register_macro(script_name, script_description, main)