How to make persistent buffer list above frame like in vim powerline

Have you tried C-x C-b (list-buffers)? That gives you a list of buffers in another window. It will remain visible, depending on what keys you use to access the listed buffers. ? in that window tells you what keys are available:

Buffer Menu mode defined in ‘buff-menu.el’: Major mode for Buffer Menu buffers. The Buffer Menu is invoked by the commands C-x C-b, M-x buffer-menu, and M-x buffer-menu-other-window. See ‘buffer-menu’ for a description of its contents. In Buffer Menu mode, the following commands are defined: q Remove the Buffer Menu from the display. RET Select current line’s buffer in place of the buffer menu. o Select that buffer in another window, so the Buffer Menu remains visible in its window. V Select current line’s buffer, in View mode. M-x Buffer-menu-view-other-window Select that buffer in another window, in view-mode. C-o Make another window display that buffer. m Mark current line’s buffer to be displayed. v Select current line’s buffer. Also show buffers marked with m, in other windows. 1 Select that buffer in full-frame window. 2 Select that buffer in one window, together with the buffer selected before this one in another window. M-s a C-s Incremental search in the marked buffers. M-s a C-M-s Isearch for regexp in the marked buffers. M-s a C-o Show lines matching regexp in the marked buffers. t visit-tags-table this buffer. ~ Clear modified-flag on that buffer. s Mark that buffer to be saved, and move down. C-k Mark that buffer to be deleted, and move down. C-d Mark that buffer to be deleted, and move up. x Delete or save marked buffers. u Remove all marks from current line. With prefix argument, also move up one line. DEL Back up a line and remove marks. % Toggle read-only status of buffer on this line. g Update the list of buffers. T Toggle whether the menu displays only file buffers. b Bury the buffer listed on this line.