diff --git a/brainspace/plotting/colormaps.py b/brainspace/plotting/colormaps.py
index cb8af5b..b3d7a50 100644
--- a/brainspace/plotting/colormaps.py
+++ b/brainspace/plotting/colormaps.py
@@ -9,4 +9,57 @@
                         [70, 130, 180, 255],
                         [196, 58, 250, 255]], dtype=np.uint8)
 
-colormaps = {'yeo7': yeo7_colors}
+eco_kos_colors = np.array([[0, 0, 0, 255],
+                           [126, 40, 127, 255],
+                           [51, 104, 156, 255],
+                           [167, 210, 140, 255],
+                           [254, 205, 8, 255],
+                           [255, 253, 25, 255]], dtype=np.uint8)
+
+# 5-step Spectral palette (control points from ColorBrewer 2.0, Apache 2.0).
+# Reference: https://colorbrewer2.org
+spec_5_colors = np.array([[0, 0, 0, 255],
+                          [50, 136, 189, 255],
+                          [171, 221, 164, 255],
+                          [235, 235, 181, 255],
+                          [253, 174, 97, 255],
+                          [213, 62, 79, 255]], dtype=np.uint8)
+
+
+def _interp_lut(stops, n=256):
+    """Build a 256-row RGBA uint8 lookup by linearly interpolating ``stops``.
+
+    ``stops`` is an (k, 3) or (k, 4) array of RGB(A) values in [0, 255].
+    Output always has alpha = 255 unless explicit alphas are provided.
+    """
+    stops = np.asarray(stops, dtype=np.float64)
+    k = stops.shape[0]
+    xs = np.linspace(0.0, 1.0, k)
+    grid = np.linspace(0.0, 1.0, n)
+    cols = stops.shape[1]
+    out = np.empty((n, 4), dtype=np.float64)
+    for c in range(min(cols, 4)):
+        out[:, c] = np.interp(grid, xs, stops[:, c])
+    if cols < 4:
+        out[:, 3] = 255.0
+    return np.clip(out, 0, 255).astype(np.uint8)
+
+
+# Diverging blue->grey->red colormap. Built programmatically from 5 control
+# points to keep the file small and reviewable instead of hand-listing 256
+# RGB tuples.
+_BuGyRd_stops = np.array([
+    [33, 113, 181],   # blue
+    [120, 170, 210],  # light blue
+    [200, 200, 200],  # grey midpoint
+    [220, 90, 60],    # warm red
+    [103, 0, 13],     # dark red
+])
+BuGyRd = _interp_lut(_BuGyRd_stops, n=256)
+
+colormaps = {
+    'yeo7': yeo7_colors,
+    'eco_kos': eco_kos_colors,
+    'spec_5': spec_5_colors,
+    'BuGyRd': BuGyRd,
+}
diff --git a/brainspace/plotting/surface_plotting.py b/brainspace/plotting/surface_plotting.py
index 0f23069..fc74233 100644
--- a/brainspace/plotting/surface_plotting.py
+++ b/brainspace/plotting/surface_plotting.py
@@ -24,7 +24,13 @@
 orientations = {'medial': (0, -90, -90),
                 'lateral': (0, 90, 90),
                 'ventral': (0, 180, 0),
-                'dorsal': (0, 0, 0)}
+                'dorsal': (0, 0, 0),
+                'anterior': (90, 90, 90),
+                'posterior': (270, 90, 90),
+                # 'flatL'/'flatR' assume an already-flattened surface; the
+                # camera angle alone does not flatten a folded mesh.
+                'flatL': (0, 180, 90),
+                'flatR': (0, 180, 270)}
 
 
 def _add_colorbar(ren, lut, location, **cb_kwds):
diff --git a/brainspace/tests/test_colormaps.py b/brainspace/tests/test_colormaps.py
new file mode 100644
index 0000000..e80e904
--- /dev/null
+++ b/brainspace/tests/test_colormaps.py
@@ -0,0 +1,31 @@
+"""Tests for plotting.colormaps registrations and BuGyRd interpolation (#91)."""
+
+import numpy as np
+
+from brainspace.plotting.colormaps import (
+    colormaps, yeo7_colors, eco_kos_colors, spec_5_colors, BuGyRd,
+)
+
+
+def test_registered_names():
+    for name in ('yeo7', 'eco_kos', 'spec_5', 'BuGyRd'):
+        assert name in colormaps
+        cm = colormaps[name]
+        assert cm.dtype == np.uint8
+        assert cm.shape[1] == 4
+
+
+def test_BuGyRd_is_256_smooth_lut():
+    assert BuGyRd.shape == (256, 4)
+    assert np.all(BuGyRd[:, 3] == 255)
+    # Endpoints should match the configured stops (within rounding).
+    np.testing.assert_array_equal(BuGyRd[0, :3], [33, 113, 181])
+    np.testing.assert_array_equal(BuGyRd[-1, :3], [103, 0, 13])
+    # Smoothness: no large per-row jump in any channel.
+    diffs = np.abs(np.diff(BuGyRd[:, :3].astype(int), axis=0))
+    assert diffs.max() < 8
+
+
+def test_categorical_palettes_have_alpha_255():
+    for cm in (yeo7_colors, eco_kos_colors, spec_5_colors):
+        assert np.all(cm[:, 3] == 255)