return {
	{ 'neovim/nvim-lspconfig' },
	{
		'dense-analysis/ale',
		config = function()
			-- Run linters only on save
			vim.g.ale_lint_on_text_changed = 'never'
			vim.g.ale_lint_on_insert_leave = 0

			-- Include the linter name (e.g. 'hack' or 'hhast'), code, and message in errors
			vim.g.ale_echo_msg_format = '[%linter%] %s'
			vim.g.ale_linters = {
				hack = {'hack', 'hhast'},
				haskell = {"hlint"},
				javascript = {'eslint'},
				d = {'dmd'},
				php = {'phpcs', 'phpstan'},
				ruby = {'rubocop'},
				cpp = {},
				asm = {},
			}
			vim.g.ale_ruby_rubocop_executable = 'bundle'
			vim.g.ale_cpp_cc_options = '-std=c++17 -Wall'

			vim.g.ale_open_list = 1
			vim.g.ale_disable_lsp = 1
		end
	},
	{ -- Tag bar.
		'liuchengxu/vista.vim',
		lazy = false,
		config = function()
			vim.g.vista_default_executive = 'nvim_lsp'
		end
	},
	{
		'nvim-treesitter/nvim-treesitter',
		lazy = false,
		branch = 'master',
		build = ':TSUpdate',
		config = function()
			require'nvim-treesitter'.setup {
				ensure_installed = {
					'haskell', 'php', 'lua', 'css', 'dockerfile', 'html', 'javascript', 'markdown', 'ruby', 'vue'
				},
				highlight = {
					enable = true,
					additional_vim_regex_highlighting = true
				}
			}
		end
	},
	{
		'kevinhwang91/nvim-ufo',
		dependencies = {'kevinhwang91/promise-async'},
		config = function()
			vim.wo.foldcolumn = '1'
			vim.wo.foldlevel = 99 -- feel free to decrease the value
			vim.wo.foldenable = true

			require('ufo').setup()
		end
	},
}