diff --git a/pygmt/src/blockm.py b/pygmt/src/blockm.py
index 83ebf989a2d..75693524d6c 100644
--- a/pygmt/src/blockm.py
+++ b/pygmt/src/blockm.py
@@ -85,7 +85,7 @@ def _blockm(block_method, data, x, y, z, outfile, **kwargs):
     r="registration",
     w="wrap",
 )
-@kwargs_to_strings(R="sequence", i="sequence_comma", o="sequence_comma")
+@kwargs_to_strings(I="sequence", R="sequence", i="sequence_comma", o="sequence_comma")
 def blockmean(data=None, x=None, y=None, z=None, outfile=None, **kwargs):
     r"""
     Block average (x,y,z) data tables by mean estimation.
@@ -182,7 +182,7 @@ def blockmean(data=None, x=None, y=None, z=None, outfile=None, **kwargs):
     r="registration",
     w="wrap",
 )
-@kwargs_to_strings(R="sequence", i="sequence_comma", o="sequence_comma")
+@kwargs_to_strings(I="sequence", R="sequence", i="sequence_comma", o="sequence_comma")
 def blockmedian(data=None, x=None, y=None, z=None, outfile=None, **kwargs):
     r"""
     Block average (x,y,z) data tables by median estimation.
@@ -270,7 +270,7 @@ def blockmedian(data=None, x=None, y=None, z=None, outfile=None, **kwargs):
     r="registration",
     w="wrap",
 )
-@kwargs_to_strings(R="sequence", i="sequence_comma", o="sequence_comma")
+@kwargs_to_strings(I="sequence", R="sequence", i="sequence_comma", o="sequence_comma")
 def blockmode(data=None, x=None, y=None, z=None, outfile=None, **kwargs):
     r"""
     Block average (x,y,z) data tables by mode estimation.
diff --git a/pygmt/src/grdfilter.py b/pygmt/src/grdfilter.py
index cffcb928d22..0c8116ac708 100644
--- a/pygmt/src/grdfilter.py
+++ b/pygmt/src/grdfilter.py
@@ -26,7 +26,7 @@
     f="coltypes",
     r="registration",
 )
-@kwargs_to_strings(R="sequence")
+@kwargs_to_strings(I="sequence", R="sequence")
 def grdfilter(grid, **kwargs):
     r"""
     Filter a grid in the space (or time) domain.
diff --git a/pygmt/src/grdlandmask.py b/pygmt/src/grdlandmask.py
index c050824dc5b..93a9c369582 100644
--- a/pygmt/src/grdlandmask.py
+++ b/pygmt/src/grdlandmask.py
@@ -27,7 +27,7 @@
     V="verbose",
     r="registration",
 )
-@kwargs_to_strings(R="sequence", N="sequence", E="sequence")
+@kwargs_to_strings(I="sequence", R="sequence", N="sequence", E="sequence")
 def grdlandmask(**kwargs):
     r"""
     Create a grid file with set values for land and water.
diff --git a/pygmt/src/grdproject.py b/pygmt/src/grdproject.py
index 782d0ece58c..42734f39b72 100644
--- a/pygmt/src/grdproject.py
+++ b/pygmt/src/grdproject.py
@@ -30,7 +30,7 @@
     n="interpolation",
     r="registration",
 )
-@kwargs_to_strings(C="sequence", R="sequence")
+@kwargs_to_strings(C="sequence", D="sequence", R="sequence")
 def grdproject(grid, **kwargs):
     r"""
     Change projection of gridded data between geographical and rectangular.
diff --git a/pygmt/src/nearneighbor.py b/pygmt/src/nearneighbor.py
index 13f0f549993..1fe7e24bab8 100644
--- a/pygmt/src/nearneighbor.py
+++ b/pygmt/src/nearneighbor.py
@@ -33,7 +33,7 @@
     r="registration",
     w="wrap",
 )
-@kwargs_to_strings(R="sequence", i="sequence_comma")
+@kwargs_to_strings(I="sequence", R="sequence", i="sequence_comma")
 def nearneighbor(data=None, x=None, y=None, z=None, **kwargs):
     r"""
     Grid table data using a "Nearest neighbor" algorithm
diff --git a/pygmt/src/surface.py b/pygmt/src/surface.py
index 9ab8e7f70bc..c86ebc41e04 100644
--- a/pygmt/src/surface.py
+++ b/pygmt/src/surface.py
@@ -33,7 +33,7 @@
     r="registration",
     w="wrap",
 )
-@kwargs_to_strings(R="sequence")
+@kwargs_to_strings(I="sequence", R="sequence")
 def surface(data=None, x=None, y=None, z=None, **kwargs):
     r"""
     Grids table data using adjustable tension continuous curvature splines.