Well, env_beam would be the way to go over env_laser. Haven't ever really used or experimented much with either of them. I suppose by setting a damage setting to 0 you could get those little damage sprites and blood sprites but not actually hurt the player, if you wanted an effect like that.
A fade texture is usually a texture used for sunbeams and the like. It usually fades from a brighter color at the top to black at the bottom, though on some it fades from left to right, etc.
Use the texture browser in Hammer and search for FADE, and you'll get two fade textures, or search C0A0YELLOW or C1A3YELLOW for two different variants. They are used in conjunction with the func_illusionary with a rendermode of additive and a fxamt of usually between 40-70. Additive renders the black part of the texture invisible, and 'fades' teh texture to black the darker it gets. They look a lot better than env_beam for static beams of light, like Barney's flashlight beam in the intro train ride.